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 A212468 #6 Jun 02 2025 07:57:49 %S A212468 582440,2034200,7274268,26242268,95010466,344305566,1246724695, %T A212468 4504766041,16223101320,58162431112,207319630999,740101423056, %U A212468 2647902413670,9488805055639,34037887492235,122166508976307 %N A212468 Number of 0..3 arrays of length n+9 with sum no more than 15 in any length 10 subsequence (=50% duty cycle). %C A212468 Column 5 of A212471 %H A212468 R. H. Hardin, <a href="/A212468/b212468.txt">Table of n, a(n) for n = 1..56</a> %e A212468 Some solutions for n=3 %e A212468 ..2....0....0....2....2....2....0....0....2....2....0....2....0....2....0....2 %e A212468 ..0....0....2....0....0....2....2....0....0....0....0....2....0....0....0....0 %e A212468 ..0....0....0....2....0....2....2....0....0....0....2....0....0....0....0....2 %e A212468 ..0....0....0....0....0....2....0....0....0....2....2....2....2....0....2....2 %e A212468 ..0....2....0....2....2....0....0....0....0....2....2....0....0....2....0....0 %e A212468 ..0....2....0....0....2....2....2....0....0....0....0....0....2....0....0....0 %e A212468 ..0....0....2....0....2....2....2....2....0....2....0....0....2....0....2....0 %e A212468 ..2....0....2....3....2....0....0....0....3....1....3....1....1....0....3....3 %e A212468 ..3....3....2....2....1....1....2....2....3....0....0....3....2....3....0....1 %e A212468 ..2....3....2....1....3....1....2....2....1....2....3....0....1....0....1....3 %e A212468 ..2....3....3....2....1....1....0....2....3....1....0....1....2....2....1....0 %e A212468 ..2....2....1....1....0....3....3....0....1....1....1....3....3....3....1....2 %K A212468 nonn %O A212468 1,1 %A A212468 _R. H. Hardin_ May 17 2012