cp's OEIS Frontend

A268770 Number of n X 4 0..2 arrays with some element plus some horizontally, vertically, diagonally or antidiagonally adjacent neighbor totalling two exactly once.

%I A268770 #8 Jan 15 2019 07:54:48
%S A268770 36,100,446,2296,10340,46312,198114,837848,3472210,14245712,57796288,
%T A268770 232692368,930069146,3696103032,14612457534,57516087912,225502135332,
%U A268770 881077245816,3431904293122,13330760323672,51652205043266
%N A268770 Number of n X 4 0..2 arrays with some element plus some horizontally, vertically, diagonally or antidiagonally adjacent neighbor totalling two exactly once.
%H A268770 R. H. Hardin, <a href="/A268770/b268770.txt">Table of n, a(n) for n = 1..210</a>
%F A268770 Empirical: a(n) = 4*a(n-1) + 10*a(n-2) - 32*a(n-3) - 47*a(n-4) + 40*a(n-5) + 38*a(n-6) - 12*a(n-7) - 9*a(n-8) for n>10.
%F A268770 Empirical g.f.: 2*x*(18 - 22*x - 157*x^2 + 332*x^3 + 794*x^4 - 238*x^5 - 734*x^6 - 72*x^7 + 189*x^8 + 54*x^9) / (1 - 2*x - 7*x^2 + 2*x^3 + 3*x^4)^2. - _Colin Barker_, Jan 15 2019
%e A268770 Some solutions for n=4:
%e A268770 ..0..0..0..0. .0..0..0..0. .0..0..0..0. .2..1..2..2. .1..1..0..0
%e A268770 ..1..0..0..1. .0..1..0..0. .0..0..1..0. .2..2..2..2. .0..0..0..0
%e A268770 ..1..0..0..0. .0..0..0..1. .1..0..0..0. .2..2..2..2. .0..0..0..0
%e A268770 ..0..0..0..0. .0..0..0..1. .0..1..0..0. .1..1..2..1. .0..0..0..0
%Y A268770 Column 4 of A268774.
%K A268770 nonn
%O A268770 1,1
%A A268770 _R. H. Hardin_, Feb 13 2016