A266126 Number of n X 3 integer arrays with each element equal to the number of horizontal, diagonal and antidiagonal neighbors exactly one smaller than itself.

4, 25, 77, 385, 2099, 9083, 48188, 249446, 1166325, 6288299, 31791039, 153857132, 834409385, 4178055126, 20594948568, 111887135749, 558869714981, 2784252991713, 15113219048778, 75548474928693, 378923024757908

Offset

1,1

Comments

Column 3 of A266131.

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-2) +205*a(n-3) -120*a(n-4) -258*a(n-5) -10662*a(n-6) -1620*a(n-7) +5336*a(n-8) +88936*a(n-9) +201296*a(n-10) +58144*a(n-11) +86672*a(n-12) -1097792*a(n-13) -831920*a(n-14) -2968704*a(n-15) -782336*a(n-16) -723152*a(n-17) +635968*a(n-18) +3427456*a(n-19) +337216*a(n-20) -204224*a(n-21) -289664*a(n-22) -453120*a(n-23) +20992*a(n-24) -1536*a(n-25) -12288*a(n-26) for n>27.

Example

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

Crossrefs

Cf. A266131.

Sequence in context: A302821 A125309 A273361 * A303514 A041991 A027764

Adjacent sequences: A266123 A266124 A266125 * A266127 A266128 A266129

Keyword

nonn

Author

R. H. Hardin, Dec 21 2015

Status

approved