A262473 Number of (3+1) X (n+1) 0..1 arrays with each row divisible by 3 and each column divisible by 5, read as a binary number with top and left being the most significant bits.

4, 9, 36, 121, 484, 1849, 7396, 29241, 116964, 466489, 1865956, 7458361, 29833444, 119311929, 477247716, 1908903481, 7635613924, 30542106169, 122168424676, 488672300601, 1954689202404, 7818751217209, 31275004868836, 125099997105721

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 5*a(n-2) - 20*a(n-3) - 4*a(n-4) + 16*a(n-5).

Empirical g.f.: x*(4 - 7*x - 20*x^2 + 12*x^3 + 16*x^4) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 + 2*x)*(1 - 4*x)). - Colin Barker, Dec 31 2018

Example

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

Crossrefs

Row 3 of A262472.

Sequence in context: A149143 A149144 A149145 * A001256 A372211 A227253

Adjacent sequences: A262470 A262471 A262472 * A262474 A262475 A262476

Keyword

nonn

Author

R. H. Hardin, Sep 23 2015

Status

approved