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A264515 Number of (n+1)X(3+1) arrays of permutations of 0..n*4+3 with each element having directed index change -1,0 0,2 -1,-2 or 1,0.

%I A264515 #4 Nov 16 2015 17:10:36
%S A264515 1,1,9,36,144,576,2116,8281,31329,121801,467856,1809025,6969600,
%T A264515 26884225,103632400,399560121,1540484001,5939322489,22899558276,
%U A264515 88289802496,340406901136,1312449766884,5060209759081,19509827162049,75220946346001
%N A264515 Number of (n+1)X(3+1) arrays of permutations of 0..n*4+3 with each element having directed index change -1,0 0,2 -1,-2 or 1,0.
%C A264515 Column 3 of A264520.
%H A264515 R. H. Hardin, <a href="/A264515/b264515.txt">Table of n, a(n) for n = 1..210</a>
%F A264515 Empirical: a(n) = 3*a(n-1) +7*a(n-2) -17*a(n-3) -5*a(n-4) +60*a(n-5) +8*a(n-6) -24*a(n-7) -36*a(n-8) +36*a(n-11) +24*a(n-12) -8*a(n-13) -60*a(n-14) +5*a(n-15) +17*a(n-16) -7*a(n-17) -3*a(n-18) +a(n-19)
%e A264515 Some solutions for n=4
%e A264515 ..4..5..0..7....4..5..0..1....4..5..6..7....6..5..0..1....4..7..0..1
%e A264515 ..8..1..2..3....8.11..2..3....0..1..2..3...10.11..2..3...10.11..2..3
%e A264515 .14.15..6..9...14.15..6..7...14.15..8..9....4.15..8..7...14..5..6..9
%e A264515 .18.19.10.11...18..9.10.19...18.19.10.11...16..9.18.19....8.17.18.19
%e A264515 .12.13.16.17...12.13.16.17...12.13.16.17...12.13.14.17...12.13.16.15
%Y A264515 Cf. A264520.
%K A264515 nonn
%O A264515 1,3
%A A264515 _R. H. Hardin_, Nov 16 2015