A264314 Number of (1+1)X(n+1) arrays of permutations of 0..n*2+1 with each element having directed index change 0,0 0,1 1,0 -1,-2 or 0,2.

1, 6, 20, 52, 140, 392, 1117, 3155, 8845, 24812, 69780, 196280, 551796, 1550968, 4359845, 12256597, 34456053, 96861618, 272293072, 765462092, 2151848328, 6049218000, 17005386025, 47805050375, 134388206025, 377788338296

Offset

1,2

Comments

Row 1 of A264313.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +a(n-2) +2*a(n-3) +5*a(n-4) -a(n-6) -8*a(n-7) -3*a(n-8) +6*a(n-9) -a(n-10) -2*a(n-11) -a(n-12) +a(n-14)

Example

Some solutions for n=4
..7..1..2..3..4....7..8..0..1..4....7..8..1..3..4....0..8..9..3..2
..0..6..5..8..9....5..6..2..3..9....0..5..2..6..9....5..1..6..7..4

Crossrefs

Cf. A264313.

Sequence in context: A122225 A275112 A027178 * A055909 A036596 A298408

Adjacent sequences: A264311 A264312 A264313 * A264315 A264316 A264317

Keyword

nonn

Author

R. H. Hardin, Nov 11 2015

Status

approved