A268773 Number of nX7 0..2 arrays with some element plus some horizontally, vertically, diagonally or antidiagonally adjacent neighbor totalling two exactly once.

576, 1456, 17000, 198114, 2258084, 24222418, 255353744, 2624246370, 26623649020, 266457432340, 2642221357236, 25977398801092, 253689171829452, 2462722401530246, 23787359898720204, 228742960985861366

Offset

1,1

Comments

Column 7 of A268774.

Links

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

Formula

Empirical: a(n) = 12*a(n-1) +64*a(n-2) -942*a(n-3) -1476*a(n-4) +26868*a(n-5) +2249*a(n-6) -376788*a(n-7) +333472*a(n-8) +2686292*a(n-9) -4376424*a(n-10) -8985248*a(n-11) +21881197*a(n-12) +12658940*a(n-13) -55768960*a(n-14) +923990*a(n-15) +80699088*a(n-16) -25850884*a(n-17) -69171189*a(n-18) +34934900*a(n-19) +34833816*a(n-20) -22502076*a(n-21) -9502460*a(n-22) +7752808*a(n-23) +1023260*a(n-24) -1356480*a(n-25) +55136*a(n-26) +94080*a(n-27) -14400*a(n-28) for n>30

Example

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

Crossrefs

Cf. A268774.

Sequence in context: A060678 A254848 A235181 * A250789 A137484 A189990

Adjacent sequences: A268770 A268771 A268772 * A268774 A268775 A268776

Keyword

nonn

Author

R. H. Hardin, Feb 13 2016

Status

approved