A262316 Number of (n+2)X(4+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.

10, 27, 133, 1618, 6043, 42661, 683218, 4276587, 39384421, 511294354, 4145349211, 40383402661, 455304705490, 4148740666347, 41070560499493, 433051832901778, 4157030255637403, 41395269270386341, 423634866109163218

Offset

1,1

Comments

Column 4 of A262319.

Links

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

Formula

Empirical: a(n) = 13*a(n-1) -30*a(n-2) +775*a(n-3) -10075*a(n-4) +23250*a(n-5) -187265*a(n-6) +2434445*a(n-7) -5617950*a(n-8) +18375455*a(n-9) -238880915*a(n-10) +551263650*a(n-11) -585288123*a(n-12) +7608745599*a(n-13) -17558643690*a(n-14) -12851058675*a(n-15) +167063762775*a(n-16) -385531760250*a(n-17) +757921180765*a(n-18) -9852975349945*a(n-19) +22737635422950*a(n-20) -1115961555955*a(n-21) +14507500227415*a(n-22) -33478846678650*a(n-23) -69403913471776*a(n-24) +902250875133088*a(n-25) -2082117404153280*a(n-26) -67517783528000*a(n-27) +877731185864000*a(n-28) -2025533505840000*a(n-29)

Example

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

Crossrefs

Cf. A262319.

Sequence in context: A179546 A119548 A219629 * A362737 A262919 A370672

Adjacent sequences: A262313 A262314 A262315 * A262317 A262318 A262319

Keyword

nonn

Author

R. H. Hardin, Sep 17 2015

Status

approved