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Number of (4+1)X(n+1) arrays of permutations of 0..n*5+4 with each element having directed index change -2,0 -1,0 0,-1 or 1,1.
1

%I #4 Nov 19 2015 06:59:26

%S 1,8,22,108,684,2736,13556,68972,316068,1534532,7430832,35311040,

%T 170094764,817176616,3914397580,18804795120,90252696296,433011737840,

%U 2078662232124,9975949817428,47876003240128,229786823307824

%N Number of (4+1)X(n+1) arrays of permutations of 0..n*5+4 with each element having directed index change -2,0 -1,0 0,-1 or 1,1.

%C Row 4 of A264628.

%H R. H. Hardin, <a href="/A264631/b264631.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) +36*a(n-3) -18*a(n-4) +186*a(n-5) +83*a(n-6) +144*a(n-7) +684*a(n-8) -1872*a(n-9) +508*a(n-10) -5048*a(n-11) -3240*a(n-12) +720*a(n-13) -95040*a(n-14) +3072*a(n-15) +3456*a(n-16) +13824*a(n-18) for n>21

%e Some solutions for n=4

%e ..1.11..7..4..9....1..6..3..4..9....1..2..3..4.14....1..2.12..4.14

%e ..6..0.12..2..3...10..0..8..2.14...15..0.17..9.19....6..0..8..9..3

%e .20..5.13.14..8...20..5.22..7.19...20..5..6..7..8...15..5.13..7.19

%e .16.10.22.19.24...16.17.11.12.13...16.10.11.12.13...20.10.11.23.24

%e .21.15.23.17.18...21.15.23.24.18...21.22.23.24.18...21.22.16.17.18

%Y Cf. A264628.

%K nonn

%O 1,2

%A _R. H. Hardin_, Nov 19 2015