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%I #7 Dec 29 2023 21:35:22
%S 256,20000,6250000,1500625000,922368160000,410018473428480,
%T 371968759094317056,244967687215822061568,286806250077948918890496,
%U 248333886971163312349814784,348300471444720308054703841536
%N Number of (n+1) X (n+1) 0..3 arrays with nondecreasing sum of every two consecutive values in every row and column.
%C Diagonal of A251974.
%H R. H. Hardin, <a href="/A251968/b251968.txt">Table of n, a(n) for n = 1..12</a>
%e Some solutions for n=2
%e ..3..2..3....1..0..2....1..0..1....2..1..2....1..0..2....1..0..1....0..0..1
%e ..0..1..0....0..1..3....3..0..3....2..1..3....1..1..1....2..2..3....0..3..1
%e ..3..2..3....1..3..3....1..3..1....3..3..3....3..3..3....3..1..3....2..3..2
%Y Cf. A251974.
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 12 2014