cp's OEIS Frontend

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.

A224261 Number of n X 7 0..2 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing.

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%I A224261 #7 Mar 18 2025 22:32:48
%S A224261 239,9503,119367,850875,4542734,20568693,83124099,306179180,
%T A224261 1038489172,3266157979,9583669559,26387428383,68551067596,
%U A224261 168889679757,396460357949,890533215416,1921389717480,3995624313351,8033215042947,15657425192703,29658055171558,54715516508103
%N A224261 Number of n X 7 0..2 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing.
%H A224261 R. H. Hardin, <a href="/A224261/b224261.txt">Table of n, a(n) for n = 1..210</a>
%F A224261 Empirical: a(n) = (118519/21794572800)*n^14 + (2257/124540416)*n^13 + (11489/13305600)*n^12 + (227251/47900160)*n^11 + (39637/777600)*n^10 + (458077/1451520)*n^9 + (169757921/76204800)*n^8 + (6354631/870912)*n^7 + (526598447/7257600)*n^6 + (85059797/2177280)*n^5 + (6141145069/8553600)*n^4 - (2165544719/1995840)*n^3 - (174076430267/75675600)*n^2 - (921446093/36036)*n + 109916 for n>8.
%e A224261 Some solutions for n=3:
%e A224261 ..0..0..2..2..1..0..0....0..0..1..1..0..0..0....0..1..1..1..1..2..1
%e A224261 ..1..2..2..2..2..1..0....0..1..1..1..1..1..0....1..2..2..2..2..2..2
%e A224261 ..2..2..2..2..2..2..1....2..2..2..2..2..2..1....1..2..2..2..2..2..2
%Y A224261 Column 7 of A224262.
%K A224261 nonn
%O A224261 1,1
%A A224261 _R. H. Hardin_, Apr 02 2013
%E A224261 Name corrected by _Andrew Howroyd_, Mar 18 2025