A264528 Number of (n+1)X(2+1) arrays of permutations of 0..n*3+2 with each element having directed index change -2,-2 -1,0 0,1 or 1,0.

1, 4, 4, 19, 49, 100, 316, 766, 1883, 5221, 12797, 33376, 86922, 220743, 573264, 1477256, 3792956, 9804491, 25237000, 64989265, 167646836, 431649191, 1112482352, 2866999890, 7385967351, 19033926173, 49045740426, 126371267386

Offset

1,2

Comments

Column 2 of A264534.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 10*a(n-2) +6*a(n-3) -42*a(n-4) -40*a(n-5) +117*a(n-6) +143*a(n-7) -222*a(n-8) -266*a(n-9) +272*a(n-10) +266*a(n-11) -222*a(n-12) -143*a(n-13) +117*a(n-14) +40*a(n-15) -42*a(n-16) -6*a(n-17) +10*a(n-18) -a(n-20)

Example

Some solutions for n=4
..3..0..1....3..4..1....8..4..1....3..4..5....3..4..1....8..4..1....3..0..5
..6..7..2....0..7..2....0..7..2....0..1..2....0..7..2....0..7..2....6..1..2
.14..4..5...14.10..5....3..6..5...14..6..7...14..6..5....3.10..5...14..4..7
.12.13..8....6.13..8...12.13.14...12.13..8...12.13..8....6.13.14...12.13..8
..9.10.11....9.12.11....9.10.11....9.10.11....9.10.11....9.12.11....9.10.11

Crossrefs

Cf. A264534.

Sequence in context: A272290 A271688 A271810 * A035413 A261568 A087213

Adjacent sequences: A264525 A264526 A264527 * A264529 A264530 A264531

Keyword

nonn

Author

R. H. Hardin, Nov 17 2015

Status

approved