login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A268773 Number of nX7 0..2 arrays with some element plus some horizontally, vertically, diagonally or antidiagonally adjacent neighbor totalling two exactly once. 1
576, 1456, 17000, 198114, 2258084, 24222418, 255353744, 2624246370, 26623649020, 266457432340, 2642221357236, 25977398801092, 253689171829452, 2462722401530246, 23787359898720204, 228742960985861366 (list; graph; refs; listen; history; text; internal format)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 25 16:42 EST 2020. Contains 331245 sequences. (Running on oeis4.)