A220618 Number of ways to reciprocally link elements of an nX5 array either to themselves or to exactly one horizontal, diagonal and antidiagonal neighbor.

8, 317, 9176, 282777, 8608738, 262680517, 8011414792, 244357686173, 7453056468816, 227323314349577, 6933510501158596, 211476640729594693, 6450176661330373022, 196734631145079828705, 6000535646826871036976

Offset

1,1

Comments

Column 5 of A220621

Links

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

Formula

Empirical: a(n) = 38*a(n-1) -189*a(n-2) -1434*a(n-3) +6910*a(n-4) -3882*a(n-5) -9380*a(n-6) +9742*a(n-7) -477*a(n-8) -1476*a(n-9) +125*a(n-10)

Example

Some solutions for n=3 0=self 1=nw 3=ne 4=w 6=e 7=sw 9=se (reciprocal directions total 10)
..0..0..9..9..0....0..0..0..6..4....6..4..7..0..0....0..0..6..4..0
..0..7..0..1..1....0..6..4..9..0....9..3..0..9..0....9..6..4..6..4
..3..0..6..4..0....0..0..0..0..1....0..1..0..0..1....0..1..0..0..0

Crossrefs

Sequence in context: A081980 A264661 A231781 * A221721 A079504 A282621

Adjacent sequences: A220615 A220616 A220617 * A220619 A220620 A220621

Keyword

nonn

Author

R. H. Hardin, Dec 17 2012

Status

approved