A202731 - OEIS

%I #7 Sep 03 2022 21:48:13

%S 1,4,14,12,462,10296,184848,3010632,46867734,714602604,10794487872,

%T 162393700356,2438841262254,36600358759728,549110847639168,

%U 8237281198316304,123562802759399382,1853462610207713988

%N Number of n X 4 nonnegative integer arrays each row and column an ascent sequence (interior element no greater than one plus up-steps preceding it) and the lower right element equal to min(n,4)-1.

%C Column 4 of A202735.

%H R. H. Hardin, <a href="/A202731/b202731.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 36*a(n-1) -492*a(n-2) +3418*a(n-3) -13215*a(n-4) +28650*a(n-5) -32500*a(n-6) +15000*a(n-7) for n>10.

%e Some solutions for n=4

%e ..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0

%e ..0..0..1..1....0..0..1..1....0..1..1..1....0..0..0..1....0..1..1..1

%e ..0..1..1..2....0..0..1..2....0..0..1..2....0..0..1..2....0..1..2..2

%e ..0..1..2..3....0..1..2..3....0..1..2..3....0..1..2..3....0..1..2..3

%Y Cf. A202735.

%K nonn

%O 1,2

%A _R. H. Hardin_, Dec 23 2011