

A251146


Number of (n+1) X (5+1) 0..2 arrays with every 2 X 2 subblock summing to 4 and no 2 X 2 subblock having exactly two nonzero entries.


1



213, 299, 433, 667, 1061, 1743, 2925, 5003, 8689, 15307, 27317, 49359, 90237, 166811, 311569, 587515, 1117445, 2141775, 4132941, 8022251, 15650353, 30663019, 60294293, 118919247, 235137501, 465904763, 924738385, 1838035483, 3657558629
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OFFSET

1,1


LINKS

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


FORMULA

Empirical: a(n) = 3*a(n1)  5*a(n3) + a(n4) + 2*a(n5).
Empirical g.f.: x*(213  340*x  464*x^2 + 433*x^3 + 342*x^4) / ((1  x)*(1 + x)*(1  2*x)*(1  x  x^2)).  Colin Barker, Nov 26 2018


EXAMPLE

Some solutions for n=4:
..1..1..1..2..0..1....1..2..1..2..0..1....2..1..2..1..1..1....1..0..1..0..2..1
..0..2..0..1..1..2....0..1..0..1..1..2....0..1..0..1..1..1....2..1..2..1..1..0
..1..1..1..2..0..1....2..1..2..1..1..0....1..2..1..2..0..2....1..0..1..0..2..1
..0..2..0..1..1..2....0..1..0..1..1..2....0..1..0..1..1..1....2..1..2..1..1..0
..1..1..1..2..0..1....2..1..2..1..1..0....1..2..1..2..0..2....0..1..0..1..1..2


CROSSREFS

Column 5 of A251149.
Sequence in context: A252032 A252025 A238019 * A085309 A252024 A302256
Adjacent sequences: A251143 A251144 A251145 * A251147 A251148 A251149


KEYWORD

nonn


AUTHOR

R. H. Hardin, Nov 30 2014


STATUS

approved



