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 A251973 #6 Jul 23 2025 13:35:52 %S A251973 1500625,294122500,57648010000,4067643585600,287012931399936, %T A251973 10332465530397696,371968759094317056,8266815890892066816, %U A251973 183725765411866546176,2835563471280083174400,43763160717460467360000 %N A251973 Number of (n+1)X(7+1) 0..3 arrays with nondecreasing sum of every two consecutive values in every row and column. %C A251973 Column 7 of A251974 %H A251973 R. H. Hardin, <a href="/A251973/b251973.txt">Table of n, a(n) for n = 1..18</a> %e A251973 Some solutions for n=1 %e A251973 ..0..0..0..0..2..0..2..2....0..0..0..0..0..2..1..2....0..0..0..0..0..1..1..2 %e A251973 ..0..0..0..2..2..3..2..3....0..1..2..1..3..2..3..2....0..0..0..0..0..0..3..0 %K A251973 nonn %O A251973 1,1 %A A251973 _R. H. Hardin_, Dec 12 2014