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

Author

R. H. Hardin, Feb 13 2016

Keywords

• nonn

Comments

Column 7 of A268774.

Examples

			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
		

Links

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

Crossrefs

Cf. A268774.

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) [phone]*a(n-12) [phone]*a(n-13) -55768960*a(n-14) +923990*a(n-15) [phone]*a(n-16) -25850884*a(n-17) -69171189*a(n-18) [phone]*a(n-19) [phone]*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