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 A302278 #7 Apr 05 2018 04:09:22 %S A302278 0,1,0,1,3,0,2,7,10,0,3,10,22,23,0,5,27,29,79,61,0,8,45,74,89,269,162, %T A302278 0,13,98,162,283,353,942,421,0,21,193,363,649,1219,941,3401,1103,0,34, %U A302278 379,782,1621,3621,3854,3316,12283,2890,0,55,778,1766,4209,14125,15862,14639 %N A302278 T(n,k) = number of n X k 0..1 arrays with every element equal to 1, 2 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302278 Table starts %C A302278 0 1 1 2 3 5 8 13 21 34 %C A302278 0 3 7 10 27 45 98 193 379 778 %C A302278 0 10 22 29 74 162 363 782 1766 3953 %C A302278 0 23 79 89 283 649 1621 4209 9563 25179 %C A302278 0 61 269 353 1219 3621 14125 38410 108141 360173 %C A302278 0 162 942 941 3854 15862 72083 229708 713848 2948380 %C A302278 0 421 3401 3316 14639 69601 384916 1354563 4386347 20677591 %C A302278 0 1103 12283 12016 63093 385242 3027442 11370253 43394297 258471515 %C A302278 0 2890 43006 34060 222254 1809350 17837758 75667277 325745362 2460590443 %H A302278 R. H. Hardin, <a href="/A302278/b302278.txt">Table of n, a(n) for n = 1..220</a> %F A302278 Empirical for column k: %F A302278 k=1: a(n) = a(n-1) %F A302278 k=2: a(n) = 2*a(n-1) + a(n-2) + 2*a(n-3) - a(n-4) %F A302278 k=3: [order 18] %F A302278 k=4: [order 72] for n > 73 %F A302278 Empirical for row n: %F A302278 n=1: a(n) = a(n-1) + a(n-2) %F A302278 n=2: a(n) = a(n-1) + 3*a(n-2) - 4*a(n-4) for n > 5 %F A302278 n=3: [order 16] for n > 18 %F A302278 n=4: [order 64] for n > 66 %e A302278 Some solutions for n=5, k=4: %e A302278 0 0 1 1 0 1 1 1 0 0 0 0 0 0 0 0 0 0 1 0 %e A302278 1 1 0 0 0 0 1 0 1 1 1 1 0 1 0 1 1 1 0 0 %e A302278 1 0 1 0 0 0 0 0 0 1 0 1 1 0 1 0 0 0 0 1 %e A302278 1 0 1 0 0 1 1 1 1 0 1 0 1 1 1 1 0 1 1 1 %e A302278 0 1 0 1 1 0 0 0 0 1 0 1 0 0 0 0 1 1 0 0 %Y A302278 Column 2 is A185828. %Y A302278 Row 1 is A000045(n-1). %K A302278 nonn,tabl %O A302278 1,5 %A A302278 _R. H. Hardin_, Apr 04 2018