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 A223677 #6 Jul 23 2025 04:23:05 %S A223677 16,256,3177,35509,384009,4106403,43632367,462307835,4893189359, %T A223677 51766786082,547539109894,5790804006475,61241515380486, %U A223677 647657786582245,6849233638750700,72433084682283498,766004610399351979 %N A223677 Number of nX5 0..1 arrays with rows and antidiagonals unimodal. %C A223677 Column 5 of A223680 %H A223677 R. H. Hardin, <a href="/A223677/b223677.txt">Table of n, a(n) for n = 1..210</a> %F A223677 Empirical: a(n) = 16*a(n-1) -65*a(n-2) +116*a(n-3) -387*a(n-4) -316*a(n-5) +5502*a(n-6) -6052*a(n-7) -5304*a(n-8) +10256*a(n-9) -13182*a(n-10) +1596*a(n-11) +36430*a(n-12) -48912*a(n-13) +27205*a(n-14) -2186*a(n-15) -10400*a(n-16) +7800*a(n-17) -2128*a(n-18) +192*a(n-19) %e A223677 Some solutions for n=3 %e A223677 ..0..0..0..0..0....0..0..0..1..0....1..0..0..0..0....0..0..1..1..1 %e A223677 ..0..0..1..0..0....1..1..1..1..0....0..0..1..0..0....1..1..1..1..0 %e A223677 ..0..0..0..1..0....0..1..1..1..1....0..0..0..1..0....0..0..0..1..0 %K A223677 nonn %O A223677 1,1 %A A223677 _R. H. Hardin_ Mar 25 2013