A262315 Number of (n+2)X(3+2) 0..1 arrays with each row and column divisible by 7, read as a binary number with top and left being the most significant bits.

5, 9, 17, 133, 361, 1009, 8357, 33993, 127121, 795013, 3876585, 16907121, 90644645, 463649609, 2179845009, 11046180229, 56646588009, 276046895345, 1376462436005, 7003379302345, 34679915634321, 172507268999557, 871215356444137

Offset

1,1

Comments

Column 3 of A262319.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) +203*a(n-3) -1015*a(n-4) -17262*a(n-6) +86310*a(n-7) +803306*a(n-9) -4016530*a(n-10) -22920723*a(n-12) +114603615*a(n-13) +424713065*a(n-15) -2123565325*a(n-16) -5289109868*a(n-18) +26445549340*a(n-19) +45727616604*a(n-21) -228638083020*a(n-22) -289788580823*a(n-24) +1448942904115*a(n-25) +1453125527917*a(n-27) -7265627639585*a(n-28) -5836364956590*a(n-30) +29181824782950*a(n-31) +16212555187738*a(n-33) -81062775938690*a(n-34) -21276199455861*a(n-36) +106380997279305*a(n-37) -6355957095425*a(n-39) +31779785477125*a(n-40) +38763541794536*a(n-42) -193817708972680*a(n-43)

Example

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

Crossrefs

Cf. A262319.

Sequence in context: A262484 A228956 A233584 * A315119 A372709 A061502

Adjacent sequences: A262312 A262313 A262314 * A262316 A262317 A262318

Keyword

nonn

Author

R. H. Hardin, Sep 17 2015

Status

approved