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 A212226 #7 Jan 01 2024 10:19:49 %S A212226 50,124,311,775,1895,4663,11518,28446,70145,172951,426630,1052487, %T A212226 2596184,6403675,15795627,38963018,96109484,237070048,584773118, %U A212226 1442444418,3558040343,8776520278,21648797430,53400493513,131721540000 %N A212226 Number of 0..2 arrays of length n+3 with sum no more than 4 in any length 4 subsequence (=50% duty cycle). %C A212226 Column 2 of A212232. %H A212226 R. H. Hardin, <a href="/A212226/b212226.txt">Table of n, a(n) for n = 1..210</a> %F A212226 Empirical: a(n) = 2*a(n-1) +a(n-3) +6*a(n-4) -3*a(n-5) -a(n-6) +a(n-7) -7*a(n-8) +4*a(n-9) -a(n-10) +3*a(n-12) -4*a(n-13) -a(n-16) +a(n-17). %e A212226 Some solutions for n=3 %e A212226 ..0....0....2....1....0....1....1....1....0....1....1....0....1....1....1....1 %e A212226 ..0....1....1....2....1....2....1....1....1....0....1....2....2....1....0....0 %e A212226 ..1....0....1....1....0....0....2....0....0....0....0....2....0....1....1....0 %e A212226 ..0....0....0....0....0....1....0....1....0....2....2....0....1....1....0....1 %e A212226 ..2....0....2....0....2....0....1....0....1....1....1....0....1....0....2....2 %e A212226 ..1....0....1....0....0....0....1....1....0....1....0....2....2....1....1....0 %Y A212226 Cf. A212232. %K A212226 nonn %O A212226 1,1 %A A212226 _R. H. Hardin_, May 06 2012