A264564 Number of (n+1)X(3+1) arrays of permutations of 0..n*4+3 with each element having directed index change 1,0 1,1 0,-1 or -1,1.

1, 4, 10, 31, 79, 224, 646, 1784, 5010, 14026, 39283, 110214, 308476, 864321, 2421872, 6784237, 19008032, 53250952, 149186453, 417966045, 1170955616, 3280543940, 9190733824, 25748605578, 72137045260, 202098106485, 566195445452

Offset

1,2

Comments

Column 3 of A264569.

Links

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

Formula

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)

Example

Some solutions for n=4
..1..4..3..6....1..4..3..6....1..4..3..6....1..2..5..6....1..2..5..6
..5..0..7..2....5..0..2.10....5..0..7..2....0..8..7..3....0..8..7..3
..9.12.13.14....9.12.13..7....9.10.11.14....9..4.11.14....9..4.11.14
..8.16.10.11....8.16.15.11....8.16.17.18...13.16.17.10...13.16.10.18
.17.18.19.15...17.18.19.14...12.13.19.15...12.18.19.15...17.12.19.15

Crossrefs

Cf. A264569.

Sequence in context: A145453 A346754 A333916 * A304963 A034730 A321143

Adjacent sequences: A264561 A264562 A264563 * A264565 A264566 A264567

Keyword

nonn

Author

R. H. Hardin, Nov 17 2015

Status

approved