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A264622 Number of (n+1) X (1+1) arrays of permutations of 0..n*2+1 with each element having directed index change -2,0 -1,0 0,-1 or 1,1. 1

%I #8 Jan 08 2019 12:29:42

%S 0,1,2,1,1,4,6,5,7,15,21,23,34,58,80,101,149,230,319,431,629,928,1299,

%T 1810,2617,3784,5336,7536,10828,15521,21992,31236,44713,63862,90741,

%U 129177,184524,263178,374521,533619,761403,1085401,1545839,2203162

%N Number of (n+1) X (1+1) arrays of permutations of 0..n*2+1 with each element having directed index change -2,0 -1,0 0,-1 or 1,1.

%H R. H. Hardin, <a href="/A264622/b264622.txt">Table of n, a(n) for n = 1..210</a>

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

%F Empirical g.f.: x^2*(1 + x)^2 / (1 - x^3 - 2*x^4 - x^5). - _Colin Barker_, Jan 08 2019

%e All solutions for n=4:

%e ..1..5

%e ..3..0

%e ..8..2

%e ..7..4

%e ..9..6

%Y Column 1 of A264628.

%K nonn

%O 1,3

%A _R. H. Hardin_, Nov 19 2015

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Last modified March 29 06:15 EDT 2024. Contains 371265 sequences. (Running on oeis4.)