A221633 Equals one maps: number of 2 X n binary arrays indicating the locations of corresponding elements equal to exactly one of their horizontal, diagonal and antidiagonal neighbors in a random 0..3 2 X n array.

1, 8, 37, 176, 787, 3480, 14865, 62064, 254463, 1032248, 4160093, 16707056, 66965547, 268146328, 1073157737, 4293797168, 17177516055, 68714775736, 274868469813, 1099492794416, 4398008728003, 17592110670488, 70368592998337

Offset

1,2

Comments

Row 2 of A221632.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) - 3*a(n-2) - 32*a(n-3) + 45*a(n-4) + 30*a(n-5) - 77*a(n-6) + 12*a(n-7) + 36*a(n-8) - 16*a(n-9) for n>10.

Empirical g.f.: x*(1 + 2*x - 8*x^2 + 10*x^3 + 53*x^4 + 80*x^5 + 150*x^6 + 72*x^7 + 56*x^8 -32*x^9) / ((1 - x)^4*(1 + x)^2*(1 - 2*x)*(1 + 2*x)*(1 - 4*x)). - Colin Barker, Aug 10 2018

Example

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

Crossrefs

Cf. A221632.

Sequence in context: A220917 A221891 A221063 * A201452 A128246 A257215

Adjacent sequences: A221630 A221631 A221632 * A221634 A221635 A221636

Keyword

nonn

Author

R. H. Hardin, Jan 21 2013

Status

approved