A266034 Number of 2Xn integer arrays with each element equal to the number of horizontal and antidiagonal neighbors less than itself.

1, 11, 50, 315, 2142, 13796, 89487, 578659, 3745788, 24284259, 157359111, 1019384424, 6604244679, 42788807569, 277226538674, 1796117279879, 11636814263230, 75393615576296, 488467052221866, 3164723563461521

Offset

1,2

Comments

Row 2 of A266033.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +11*a(n-2) +51*a(n-3) +156*a(n-4) +141*a(n-5) -429*a(n-6) -2785*a(n-7) -5505*a(n-8) -4470*a(n-9) +6355*a(n-10) +33613*a(n-11) +32025*a(n-12) -21483*a(n-13) -43190*a(n-14) -23519*a(n-15) -2201*a(n-16) +16965*a(n-17) +9808*a(n-18) -2953*a(n-19) -715*a(n-20) +1191*a(n-21) -528*a(n-22) -3*a(n-23) +143*a(n-24) -39*a(n-25) +15*a(n-26)

Example

Some solutions for n=4
..0..2..3..0....0..0..0..0....0..1..1..1....0..1..1..2....0..0..3..0
..0..0..0..0....1..2..3..0....2..0..0..1....1..0..0..1....1..2..0..0

Crossrefs

Cf. A266033.

Sequence in context: A211920 A167423 A026618 * A026684 A181619 A067983

Adjacent sequences: A266031 A266032 A266033 * A266035 A266036 A266037

Keyword

nonn

Author

R. H. Hardin, Dec 20 2015

Status

approved