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 A223964 #6 Jul 23 2025 04:42:52 %S A223964 256,5864,41006,176893,594286,1718057,4500818,10981150,25334630, %T A223964 55772240,117841845,239976226,472531867,902107834,1673660678, %U A223964 3023882381,5330533450,9183978785,15489123731,25608363453,41559120445,66283141375 %N A223964 Number of 4Xn 0..3 arrays with antidiagonals unimodal and rows and diagonals nondecreasing. %C A223964 Row 4 of A223961 %H A223964 R. H. Hardin, <a href="/A223964/b223964.txt">Table of n, a(n) for n = 1..210</a> %F A223964 Empirical: a(n) = (1/1036800)*n^12 + (1/34560)*n^11 + (4379/7257600)*n^10 + (757/80640)*n^9 + (257687/2419200)*n^8 + (82939/80640)*n^7 + (8187071/1036800)*n^6 + (1661651/34560)*n^5 + (117000427/453600)*n^4 + (10787803/20160)*n^3 - (153061829/50400)*n^2 + (3421969/840)*n + 275 for n>5 %e A223964 Some solutions for n=3 %e A223964 ..0..1..1....1..2..2....0..1..1....0..0..1....0..1..2....0..0..2....0..1..2 %e A223964 ..0..2..3....1..2..3....1..1..2....1..3..3....0..3..3....0..2..3....0..3..3 %e A223964 ..2..3..3....1..1..3....0..2..2....1..1..3....1..2..3....0..1..2....1..1..3 %e A223964 ..2..2..3....0..1..3....0..2..3....0..1..2....1..3..3....1..3..3....0..2..2 %K A223964 nonn %O A223964 1,1 %A A223964 _R. H. Hardin_ Mar 29 2013