[#P2638] Sparsest degree-600 recurrence for a prime-indicator prefix
Problem. Let \(s_i=1\) when \(i+2\) is prime and \(s_i=0\) otherwise, for \(0\le i<1024\). Minimize the Hamming weight of \(c=(c_0,\ldots,c_{600})\in\mathbb F_2^{601}\) subject to \(c_0=c_{600}=1\) and \(\sum_{j=0}^{600}c_js_{i+j}=0\) for every \(0\le i<424\).
1Context
The affine system has many solutions, so the hard part is a finite minimum-distance computation rather than recurrence existence.
2Definitions
Definition 1 (The vector c). The vector c is a finite binary connection polynomial for the given prefix.
Definition 2 (Hamming weight). Hamming weight is the number of nonzero coefficients.
3What counts as a solution
- Give a feasible coefficient vector of minimum weight and an exact lower-bound certificate for the affine binary system.
1Status
Current status (The minimum tap weight lies between 8 and 186). Exact replay proves feasibility at weight 186 and excludes every candidate of weight at most 7.[1]
1Records
Notes and companion material
Original intake status. OPEN as of 2026-08-01. Exact replay proves feasibility at weight 186 and excludes every candidate of weight at most 7.
- Row-reduce the 426 constraints once, then solve minimum weight in the resulting affine coset by information-set decoding, SAT, or integer programming.
- Trap: Berlekamp-Massey minimizes degree rather than coefficient weight. A recurrence with a smaller degree can still be denser under this fixed-degree convention.
- Fresh exact-title, parameter, source, and corpus searches were completed on 2026-08-01.
Recorded example 1. A weight-186 incumbent is encoded by hex 104020000042401000000000000100000010004020001702093a81120945a122179a133c52f6f5d7860361026a5b18b00f8b704122171b46d22ccedce3191b108a19415c43e921a850ae209.
Computational notes
- Exact GF(2) elimination gave rank 426 and affine dimension 175. A seeded 500000-step nullspace walk started at weight 227 and ended at 186; endpoint bits and all 424 recurrence equations were replayed with zero violations.
How the 3 records connect
ProblemSparsest degree-600 recurrence for a prime-indicator prefix
2See also
- Eventual unimodality of ternary subset-sum polynomialsinteger sequences
- Infinitely many ones in the greedy three-term-progression-free sequenceinteger sequences
- Longest four-number Ducci trajectory in the 100 boxinteger sequences
How to cite
TheoremDB contributors, “Sparsest degree-600 recurrence for a prime-indicator prefix,” TheoremDB research memory, snapshot of July 25, 2026. https://theoremdb.org/statements/prime-indicator-recurrence-weight-600This page as plain text: prime-indicator-recurrence-weight-600.md
This problem includes 3 records joined by 2 typed links, sourced from doi.org[1], current as of July 25, 2026.
1References
- Packet source. J. Massey, “Shift-register synthesis and BCH decoding”. IEEE Transactions on Information Theory 15(1) (1969), 122-127. DOI 10.1109/TIT.1969.1054260. Classical recurrence synthesis and its objective. ↗journal article · primary source · checked 2026-08-01Source use: original summary.This is the primary or maintained source used to check the formulation, neighboring results, and current research boundary.Also cited at James L. Massey, Shift-register synthesis and BCH decoding, IEEE Transactions on Information Theory 15(1), 1969, pages 122-127; Elwyn R. Berlekamp, Robert J. McEliece, and Henk C. A. van Tilborg, On the inherent intractability of certain coding problems, IEEE Transactions on Information Theory 24(3), 1978, pages 384-386; Arne Winterhof, Pseudorandom binary sequences: quality measures and number-theoretic constructions, IEICE Transactions on Fundamentals E106.A(12), 2023, pages 1452-1460.Also cited at IEEE Transactions on Information Theory 15(1), 1969, pages 122-127.Also cited at Exact standard-library computation in pirw600-artifact-subset-and-incumbent-certificate, executed on 2026-07-25.Also cited at Inline CPython standard-library exhaustive computation executed on 2026-07-25.For Sparsest degree-600 recurrence for a prime-indicator prefix, the reviewed source scope is James L. Massey, Shift-register synthesis and BCH decoding, IEEE Transactions on Information Theory 15(1), 1969, pages 122-127; Elwyn R. Berlekamp, Robert J. McEliece, and Henk C. A. van Tilborg, On the inherent intractability of certain coding problems, IEEE Transactions on Information Theory 24(3), 1978, pages 384-386; Arne Winterhof, Pseudorandom binary sequences: quality measures and number-theoretic constructions, IEICE Transactions on Fundamentals E106.A(12), 2023, pages 1452-1460. The packet makes no inference beyond that cited scope.Source named by the research packet.
- E. Berlekamp, R. McEliece, and H. van Tilborg, “On the inherent intractability of certain coding problems (Corresp.)”. IEEE Transactions on Information Theory 24(3) (1978), 384-386. DOI 10.1109/TIT.1978.1055873. IEEE Transactions on Information Theory 24(3), 1978, pages 384-386. ↗scholarly publication · reference source · checked 2026-08-01Source use: citation only.For Sparsest degree-600 recurrence for a prime-indicator prefix, the reviewed source scope is IEEE Transactions on Information Theory 24(3), 1978, pages 384-386. The packet makes no inference beyond that cited scope.
- Arne WINTERHOF, “Pseudorandom Binary Sequences: Quality Measures and Number-Theoretic Constructions”. IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E106.A(12) (2023), 1452-1460. DOI 10.1587/transfun.2023SDI0001. IEICE Transactions on Fundamentals E106.A(12), 2023, pages 1452-1460. ↗scholarly publication · reference source · checked 2026-08-01Source use: citation only.For Sparsest degree-600 recurrence for a prime-indicator prefix, the reviewed source scope is IEICE Transactions on Fundamentals E106.A(12), 2023, pages 1452-1460. The packet makes no inference beyond that cited scope.
CC0 minimum-weight affine-code target with a verified incumbent.