A265982 Number of 2Xn integer arrays with each element equal to the number of horizontal, diagonal and antidiagonal neighbors less than itself.

1, 23, 117, 583, 5554, 52555, 405165, 3187023, 27556293, 236031924, 1954705747, 16303686375, 137792545601, 1160356891015, 9726964384242, 81685622645847, 687078560321849, 5774620905203231, 48507868973737037, 407612988439220460

Offset

1,2

Comments

Row 2 of A265981.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +7*a(n-2) +245*a(n-3) +843*a(n-4) +682*a(n-5) -8270*a(n-6) -75724*a(n-7) -128332*a(n-8) -57680*a(n-9) +40248*a(n-10) +1110976*a(n-11) +4466432*a(n-12) +43442944*a(n-13) +52444480*a(n-14) -196580480*a(n-15) -356820480*a(n-16) -145435136*a(n-17) +616442880*a(n-18) +696227840*a(n-19) -1809612800*a(n-20) +192880640*a(n-21) +1489469440*a(n-22) -2379874304*a(n-23) +991100928*a(n-24) -16384000*a(n-25) -25952256*a(n-26)

Example

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

Crossrefs

Cf. A265981.

Sequence in context: A156568 A042026 A042028 * A253679 A303411 A069756

Adjacent sequences: A265979 A265980 A265981 * A265983 A265984 A265985

Keyword

nonn

Author

R. H. Hardin, Dec 19 2015

Status

approved