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 A232516 Number of (1+1) X (n+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally, diagonally or antidiagonally, with no adjacent elements equal. 1

%I #8 Dec 31 2023 17:46:53

%S 4,16,16,54,74,218,340,868,1494,3528,6466,14494,27650,59992,117432,

%T 249546,496576,1041354,2094122,4354594,8815964,18233764,37073438,

%U 76414688,155795194,320416958,654414674,1344022320,2748080744,5638905938

%N Number of (1+1) X (n+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally, diagonally or antidiagonally, with no adjacent elements equal.

%C Row 1 of A232515.

%H R. H. Hardin, <a href="/A232516/b232516.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-2) +a(n-3) +2*a(n-4) +2*a(n-5).

%F Empirical: G.f.: -2*x*(2+8*x+2*x^2+x^3+x^4) / ( -1+3*x^2+x^3+2*x^4+2*x^5 ). - _R. J. Mathar_, Nov 23 2014

%e Some solutions for n=7

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

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

%Y Cf. A232515.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 25 2013

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Last modified August 12 15:11 EDT 2024. Contains 375113 sequences. (Running on oeis4.)