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 A217952 #6 Jul 22 2025 23:43:52 %S A217952 4,16,50,130,296,610,1163,2097,3670,6434,11666,22313,44907,93206, %T A217952 194831,403141,818641,1628770,3184993,6157786,11854873,22877202, %U A217952 44459405,87168326,172249773,342083954,680463827,1351826291,2677343192,5283369867 %N A217952 Number of n element 0..3 arrays with each element the minimum of 6 adjacent elements of a random 0..3 array of n+5 elements. %C A217952 Column 6 of A217954 %H A217952 R. H. Hardin, <a href="/A217952/b217952.txt">Table of n, a(n) for n = 1..210</a> %F A217952 Empirical: a(n) = 4*a(n-1) -6*a(n-2) +4*a(n-3) -a(n-4) +6*a(n-7) -4*a(n-8) +6*a(n-9) +4*a(n-10) +5*a(n-11) +6*a(n-12) +7*a(n-13) +3*a(n-14) +5*a(n-15) +4*a(n-16) +3*a(n-17) +2*a(n-18) +a(n-19) %e A217952 Some solutions for n=4 %e A217952 ..0....0....1....1....0....3....1....0....0....2....0....2....2....1....2....3 %e A217952 ..3....0....2....3....1....3....2....1....0....2....2....2....3....2....2....2 %e A217952 ..3....3....3....3....3....2....3....1....1....1....1....2....0....2....3....1 %e A217952 ..3....2....1....0....3....2....2....0....2....0....0....2....0....1....3....1 %K A217952 nonn %O A217952 1,1 %A A217952 _R. H. Hardin_ Oct 15 2012