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A224370 Number of n X 4 0..2 arrays with rows unimodal and antidiagonals nondecreasing. 1

%I #8 Aug 30 2018 06:07:24

%S 46,698,7608,77793,800309,8297747,86251004,896856330,9325161494,

%T 96954549463,1008030060622,10480399768714,108963825909899,

%U 1132887953497801,11778544075116434,122460568078334321

%N Number of n X 4 0..2 arrays with rows unimodal and antidiagonals nondecreasing.

%C Column 4 of A224374.

%H R. H. Hardin, <a href="/A224370/b224370.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 15*a(n-1) - 58*a(n-2) + 105*a(n-3) + 20*a(n-4) - 183*a(n-5) + 220*a(n-6) + 240*a(n-7) for n>8.

%F Empirical g.f.: x*(46 + 8*x - 194*x^2 - 673*x^3 + 468*x^4 + 724*x^5 - 90*x^6 - 45*x^7) / (1 - 15*x + 58*x^2 - 105*x^3 - 20*x^4 + 183*x^5 - 220*x^6 - 240*x^7). - _Colin Barker_, Aug 30 2018

%e Some solutions for n=3:

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

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

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

%Y Cf. A224374.

%K nonn

%O 1,1

%A _R. H. Hardin_, Apr 05 2013

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Last modified March 28 17:42 EDT 2024. Contains 371254 sequences. (Running on oeis4.)