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

%I #4 Nov 14 2015 15:33:30

%S 0,4,6,16,49,124,384,1041,2868,8189,22760,63910,179095,500979,1405340,

%T 3935526,11024880,30892270,86537090,242454683,679254490,1902958308,

%U 5331384633,14936238820,41845207329,117233159460,328438385380

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

%C Column 3 of A264476.

%H R. H. Hardin, <a href="/A264471/b264471.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) +a(n-2) +6*a(n-3) -6*a(n-4) +6*a(n-5) -27*a(n-6) +5*a(n-7) -9*a(n-8) +33*a(n-9) -4*a(n-10) +7*a(n-11) -12*a(n-12) +a(n-13) -a(n-14) +a(n-15)

%e Some solutions for n=4

%e ..5..0..1..2....5..6..7..2....5..0..7..2....5..6..7..2....5..6..7..2

%e ..9..4.11..3....0..4.11..3....9..1.11..3....0..1.11..3....9..4.11..3

%e .13.14.15..7...13..8..1.10...13.14.15.10...13..8.15.10...13..0..1.10

%e ..8.18.19..6...17.18.19.14....8..4.19..6...17..4.19.14....8.18.19.14

%e .12.16.17.10...12.16..9.15...12.16.17.18...12.16..9.18...12.16.17.15

%Y Cf. A264476.

%K nonn

%O 1,2

%A _R. H. Hardin_, Nov 14 2015