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 A255994 #8 Jan 25 2018 12:00:13 %S A255994 16,32,53,80,114,156,207,268,340,424,521,632,758,900,1059,1236,1432, %T A255994 1648,1885,2144,2426,2732,3063,3420,3804,4216,4657,5128,5630,6164, %U A255994 6731,7332,7968,8640,9349,10096,10882,11708,12575,13484,14436,15432,16473,17560 %N A255994 Number of length n+3 0..1 arrays with at most one downstep in every n consecutive neighbor pairs. %C A255994 Row 3 of A255992. %H A255994 R. H. Hardin, <a href="/A255994/b255994.txt">Table of n, a(n) for n = 1..210</a> %F A255994 Empirical: a(n) = (1/6)*n^3 + (3/2)*n^2 + (31/3)*n + 4. %F A255994 Empirical g.f.: x*(16 - 32*x + 21*x^2 - 4*x^3) / (1 - x)^4. - _Colin Barker_, Jan 25 2018 %e A255994 Some solutions for n=4: %e A255994 ..0....1....0....0....1....0....1....0....1....1....0....0....1....1....0....0 %e A255994 ..1....1....0....0....1....1....1....0....0....1....1....1....1....0....1....0 %e A255994 ..0....0....0....0....1....0....0....1....0....1....1....1....1....1....0....1 %e A255994 ..1....0....1....1....0....0....0....1....0....1....1....0....0....1....0....1 %e A255994 ..1....0....0....0....0....0....1....1....0....1....0....0....0....1....0....0 %e A255994 ..1....0....0....0....1....0....1....0....1....1....0....0....0....1....1....0 %e A255994 ..1....0....1....0....1....1....1....0....1....1....1....0....0....1....1....0 %Y A255994 Cf. A255992. %K A255994 nonn %O A255994 1,1 %A A255994 _R. H. Hardin_, Mar 13 2015