OFFSET
1,1
COMMENTS
a(n) is the number of multiples of 15 from 0 to 2^(n+3)-1. - Robert Israel, Dec 31 2018
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + a(n-4) - 2*a(n-5).
Empirical g.f.: x*(2 - x - x^2 - x^3 - 2*x^4) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 + x^2)). - Colin Barker, Dec 31 2018
a(n) = floor((2^(n+3)+14)/15). This satisfies the empirical recursion and g.f. - Robert Israel, Dec 31 2018
EXAMPLE
Some solutions for n=4:
..1..1..1..1....1..1..1..1....0..0..0..0....0..0..0..0....1..1..1..1
..1..1..1..1....1..1..1..1....0..0..0..0....0..0..0..0....0..0..0..0
..1..1..1..1....0..0..0..0....1..1..1..1....0..0..0..0....1..1..1..1
..1..1..1..1....1..1..1..1....1..1..1..1....1..1..1..1....1..1..1..1
..0..0..0..0....0..0..0..0....1..1..1..1....1..1..1..1....0..0..0..0
..0..0..0..0....0..0..0..0....1..1..1..1....1..1..1..1....1..1..1..1
..0..0..0..0....1..1..1..1....0..0..0..0....1..1..1..1....0..0..0..0
MAPLE
seq(floor((2^(n+3)+14)/15), n=1..100); # Robert Israel, Dec 31 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 23 2015
STATUS
approved