A270053 - OEIS

%I #6 Mar 09 2016 12:22:37

%S 40,5400,385200,22911300,1248460920,64599504300,3230189811360,

%T 157641639369300,7554828673749960,356991331281723900,

%U 16680284779615323120,772247380917124520100,35480193258896640581400

%N Number of nX3 0..4 arrays with some element plus some horizontally or vertically adjacent neighbor totalling four exactly once.

%C Column 3 of A270058.

%H R. H. Hardin, <a href="/A270053/b270053.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 90*a(n-1) -2257*a(n-2) +10440*a(n-3) -13456*a(n-4) for n>5.

%F Empirical: g.f. 40*x -180*x^2*(-30+560*x-2395*x^2+2976*x^3) / (116*x^2-45*x+1)^2 . - _R. J. Mathar_, Mar 09 2016

%e Some solutions for n=2

%e ..3..1..4. .1..2..2. .1..1..4. .3..0..2. .2..2..0. .1..4..0. .0..0..1

%e ..4..4..2. .0..0..3. .1..2..2. .2..3..1. .0..0..0. .4..2..0. .3..1..4

%Y Cf. A270058.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 09 2016