A233603 Number of (1+2)X(n+2) 0..2 arrays with no increasing sequence of length 3 horizontally, vertically or antidiagonally downwards

15272, 341849, 7655432, 171455430, 3839022704, 85958825311, 1924641376011, 43093190215906, 964865318375114, 21603527637037559, 483707247481446040, 10830300554586216393, 242492560693344416243, 5429456145729472780602

Offset

1,1

Comments

Row 1 of A233602

Links

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

Formula

Empirical: a(n) = 26*a(n-1) -16*a(n-2) -1634*a(n-3) +2604*a(n-4) +36056*a(n-5) -49349*a(n-6) -329582*a(n-7) +280917*a(n-8) +1081611*a(n-9) -606669*a(n-10) -1800926*a(n-11) +659223*a(n-12) +1725796*a(n-13) -405251*a(n-14) -986564*a(n-15) +141685*a(n-16) +326475*a(n-17) -25199*a(n-18) -54329*a(n-19) +1736*a(n-20) +2831*a(n-21) +16*a(n-22) -64*a(n-23)

Example

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

Crossrefs

Sequence in context: A296087 A252318 A233602 * A233595 A233594 A064982

Adjacent sequences: A233600 A233601 A233602 * A233604 A233605 A233606

Keyword

nonn

Author

R. H. Hardin, Dec 14 2013

Status

approved