A263965 Number of (1+1)X(n+1) arrays of permutations of 0..n*2+1 with each element having index change (+-,+-) 0,0 1,1 or 1,2.

4, 20, 108, 465, 2265, 10920, 52752, 253176, 1221305, 5885873, 28368956, 136712788, 658952404, 3175970497, 15307435585, 73778034832, 355593913600, 1713880597360, 8260513454657, 39813787812289, 191893397639092, 924882430123988

Offset

1,1

Comments

Row 1 of A263964.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) +7*a(n-4) -140*a(n-5) +33*a(n-6) -4*a(n-7) +95*a(n-8) +792*a(n-9) +41*a(n-10) -41*a(n-12) -792*a(n-13) -95*a(n-14) +4*a(n-15) -33*a(n-16) +140*a(n-17) -7*a(n-18) -5*a(n-21) +a(n-22)

Example

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

Crossrefs

Cf. A263964.

Sequence in context: A243585 A359712 A365226 * A265084 A321111 A319321

Adjacent sequences: A263962 A263963 A263964 * A263966 A263967 A263968

Keyword

nonn

Author

R. H. Hardin, Oct 30 2015

Status

approved