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 A223915 #6 Jul 23 2025 04:38:39 %S A223915 86,1600,13347,74040,319156,1147712,3588729,10031780,25574524, %T A223915 60357024,133401811,278664144,554222764,1055811684,1936212233, %U A223915 3432395716,5902734700,9877089124,16123126195,25732854408,40234046052,61731993272 %N A223915 Number of nX5 0..2 arrays with rows and antidiagonals unimodal and columns nondecreasing. %C A223915 Column 5 of A223918 %H A223915 R. H. Hardin, <a href="/A223915/b223915.txt">Table of n, a(n) for n = 1..210</a> %F A223915 Empirical: a(n) = (1009/907200)*n^10 + (1009/60480)*n^9 + (4919/30240)*n^8 + (293/288)*n^7 + (196597/43200)*n^6 + (35317/2880)*n^5 + (1341229/45360)*n^4 + (115123/3024)*n^3 + (38483/3150)*n^2 - (868/15)*n + 4 for n>2 %e A223915 Some solutions for n=3 %e A223915 ..0..0..1..0..0....0..2..2..1..0....0..0..2..1..0....0..0..0..1..0 %e A223915 ..0..1..2..1..0....0..2..2..1..0....0..2..2..1..0....0..1..1..2..1 %e A223915 ..0..2..2..2..0....0..2..2..2..2....0..2..2..1..1....0..1..2..2..1 %K A223915 nonn %O A223915 1,1 %A A223915 _R. H. Hardin_ Mar 29 2013