

A202117


Number of 1..1 arrays of n elements with first, second and third differences also in 1..1


1



3, 7, 13, 19, 27, 35, 47, 65, 91, 129, 185, 267, 387, 563, 821, 1199, 1753, 2565, 3755, 5499, 8055, 11801, 17291, 25337, 37129, 54411, 79739, 116859, 171261, 250991, 367841, 539093, 790075, 1157907, 1696991, 2487057, 3644955, 5341937, 7828985
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OFFSET

1,1


COMMENTS

Column 1 of A202124


LINKS

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


FORMULA

Empirical: a(n) = 2*a(n1) a(n2) +a(n3) a(n4) for n>8


EXAMPLE

Some solutions for n=7
..1....1....1....0....1....1....0....0....1....1...1...1...1....1...1....0
..1....0....1...1....0....1...1....1....1....1....0...1...1....0....0....0
..1...1....1...1....0....0...1....1....1....1....0...1....0....0....1....0
..1...1....1....0....0...1...1....1....1....0....0...1....1....0....1....0
..1....0....1....1....0...1...1....0....0...1....0...1....1....0....1....0
..1....1....1....1....0....0....0...1...1...1....0...1....0....0....1....0
..0....1....1....0...1....1....1...1...1...1....1...1...1....0....0....0


CROSSREFS

Sequence in context: A102828 A117679 A276215 * A100458 A193765 A000960
Adjacent sequences: A202114 A202115 A202116 * A202118 A202119 A202120


KEYWORD

nonn


AUTHOR

R. H. Hardin Dec 11 2011


STATUS

approved



