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 A263120 #4 Oct 10 2015 07:05:36 %S A263120 36,148,522,1708,5124,15640,47602,144236,432708,1295524,3883594, %T A263120 11649676,34949028,104703688,313818418,940969804,2822909412, %U A263120 8465899188,25390861962,76159749740,228479249220,685409187320,2056136698226 %N A263120 Number of (n+3)X(2+3) 0..1 arrays with each row divisible by 15 and column not divisible by 15, read as a binary number with top and left being the most significant bits. %C A263120 Column 2 of A263124. %H A263120 R. H. Hardin, <a href="/A263120/b263120.txt">Table of n, a(n) for n = 1..210</a> %F A263120 Empirical: a(n) = 4*a(n-1) -a(n-2) -8*a(n-3) +48*a(n-4) -168*a(n-5) +48*a(n-6) +312*a(n-7) -955*a(n-8) +2884*a(n-9) -955*a(n-10) -4832*a(n-11) +7632*a(n-12) -16032*a(n-13) +7632*a(n-14) +17568*a(n-15) +4886*a(n-16) -72248*a(n-17) +4886*a(n-18) +197200*a(n-19) -366336*a(n-20) +873744*a(n-21) -366336*a(n-22) -1155888*a(n-23) +1014058*a(n-24) -588568*a(n-25) +1014058*a(n-26) -2290528*a(n-27) +6020160*a(n-28) -17209056*a(n-29) +6020160*a(n-30) +27546528*a(n-31) -27604133*a(n-32) +27776948*a(n-33) -27604133*a(n-34) +27085688*a(n-35) -75797424*a(n-36) +221932632*a(n-37) -75797424*a(n-38) -362608200*a(n-39) +362785825*a(n-40) -363318700*a(n-41) +362785825*a(n-42) -361187200*a(n-43) +406335600*a(n-44) -541780800*a(n-45) +406335600*a(n-46) %e A263120 Some solutions for n=4 %e A263120 ..1..1..1..1..0....1..1..1..1..0....0..0..0..0..0....0..1..1..1..1 %e A263120 ..1..1..1..1..0....0..0..0..0..0....0..1..1..1..1....1..1..1..1..0 %e A263120 ..0..0..0..0..0....1..1..1..1..0....0..0..0..0..0....1..1..1..1..0 %e A263120 ..0..1..1..1..1....0..1..1..1..1....1..1..1..1..0....0..1..1..1..1 %e A263120 ..1..1..1..1..0....0..0..0..0..0....1..1..1..1..0....1..1..1..1..0 %e A263120 ..1..1..1..1..0....1..1..1..1..0....0..1..1..1..1....1..1..1..1..0 %e A263120 ..1..1..1..1..0....1..1..1..1..0....1..1..1..1..0....0..1..1..1..1 %Y A263120 Cf. A263124. %K A263120 nonn %O A263120 1,1 %A A263120 _R. H. Hardin_, Oct 10 2015