This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A089980 #26 Jul 18 2025 09:33:37 %S A089980 1,1,1,1,2,1,1,3,3,1,1,5,7,5,1,1,8,17,17,8,1,1,13,41,63,41,13,1,1,21, %T A089980 99,227,227,99,21,1,1,34,239,827,1234,827,239,34,1,1,55,577,2999,6743, %U A089980 6743,2999,577,55,1,1,89,1393,10897,36787,55447,36787,10897,1393,89,1 %N A089980 Array read by antidiagonals: T(n,m) = number of independent sets in the grid graph P_n X P_m. %C A089980 This table is indexed starting at 0. The table in A089934 is 1 based. %C A089980 A181031 is essentially the same array (see the Comments by _Steve Butler_ in A006506). - _N. J. A. Sloane_, Jan 27 2015 %H A089980 Liang Kai, <a href="/A089980/b089980.txt">Antidiagonals n = 0..78, flattened</a> %H A089980 Kai Liang, <a href="https://arxiv.org/abs/2505.12776">Independent Set Enumeration in King Graphs by Tensor Network Contractions</a>, arXiv:2505.12776 [math.CO], 2025. See p. 1. %H A089980 Kai Liang, <a href="https://arxiv.org/abs/2507.04007">Independent Set Enumeration and Estimation of Related Constants of Grid Graphs</a>, arXiv:2507.04007 [math.CO], 2025. See p. 1. %e A089980 Square array T(n,m) begins: %e A089980 1, 1, 1, 1, 1, 1, ... %e A089980 1, 2, 3, 5, 8, 13, ... %e A089980 1, 3, 7, 17, 41, 99, ... %e A089980 1, 5, 17, 63, 227, 827, ... %e A089980 1, 8, 41, 227, 1234, 6743, ... %e A089980 1, 13, 99, 827, 6743, 55447, ... %Y A089980 Main entry: A089934. %Y A089980 Main diagonal gives A006506. %Y A089980 Cf. A181031. %K A089980 nonn,tabl %O A089980 0,5 %A A089980 _Mitch Harris_, Nov 17 2003