A208641 Number of 6 X n 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors

32, 233, 851, 2331, 5572, 12404, 26508, 55260, 113427, 230559, 465773, 937321, 1881726, 3772054, 7554458, 15121266, 30257157, 60531513, 121083123, 242189591, 484406152, 968843304, 1937722072, 3875484536, 7751014887, 15502081539

Offset

1,1

Comments

Row 6 of A208637.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) - 20*a(n-2) + 30*a(n-3) - 25*a(n-4) + 11*a(n-5) - 2*a(n-6) for n>9.

Conjectures from Colin Barker, Jul 05 2018: (Start)

G.f.: x*(32 + 9*x - 140*x^2 + 74*x^3 + 85*x^4 - 37*x^5 - 34*x^6 + 4*x^7 + 8*x^8) / ((1 - x)^5*(1 - 2*x)).

a(n) = (792*(7*2^n-10) - 3382*n - 539*n^2 - 38*n^3 - n^4) / 24 for n>3.

(End)

Example

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

Crossrefs

Cf. A208637.

Sequence in context: A199913 A301795 A301968 * A301889 A302085 A229400

Adjacent sequences: A208638 A208639 A208640 * A208642 A208643 A208644

Keyword

nonn

Author

R. H. Hardin, Feb 29 2012

Status

approved