A224386 - OEIS

%I #4 Apr 05 2013 12:03:25

%S 20,400,6094,86701,1268572,18794636,279128617,4142692993,61481903024,

%T 912523782542,13544525098266,201041292342421,2984053971336637,

%U 44292278131103241,657430060365000621,9758232360460992934

%N Number of nX3 0..3 arrays with diagonals and antidiagonals unimodal and rows nondecreasing

%C Column 3 of A224391

%H R. H. Hardin, <a href="/A224386/b224386.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 20*a(n-1) -70*a(n-2) -211*a(n-3) +2453*a(n-4) -12192*a(n-5) +5907*a(n-6) +119292*a(n-7) -294992*a(n-8) +742820*a(n-9) +144828*a(n-10) -5072952*a(n-11) +6034728*a(n-12) -15994872*a(n-13) -858096*a(n-14) -10368*a(n-15)

%e Some solutions for n=3

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Apr 05 2013