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A266034
Number of 2Xn integer arrays with each element equal to the number of horizontal and antidiagonal neighbors less than itself.
1
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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 20 2015
STATUS
approved