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A272967 Number of nX2 0..1 arrays with exactly n+2-2 having value 1 and no three 1s forming an isosceles triangle. 0
2, 6, 10, 21, 14, 28, 18, 29, 22, 32, 26, 36, 30, 40, 34, 44, 38, 48, 42, 52, 46, 56, 50, 60, 54, 64, 58, 68, 62, 72 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A272973.

LINKS

Table of n, a(n) for n=1..30.

FORMULA

Empirical: a(n) = a(n-1) +a(n-2) -a(n-3) for n>11

EXAMPLE

All solutions for n=3

..1..0. .1..1. .1..0. .1..0. .0..1. .1..0. .0..1. .1..1. .0..1. .0..1

..0..0. .0..0. .1..0. .1..0. .0..1. .0..1. .0..1. .0..0. .1..0. .0..0

..1..1. .1..0. .0..1. .1..0. .0..1. .0..1. .1..0. .0..1. .1..0. .1..1

CROSSREFS

Cf. A272973.

Sequence in context: A009325 A308346 A192390 * A067716 A125518 A083176

Adjacent sequences:  A272964 A272965 A272966 * A272968 A272969 A272970

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 11 2016

STATUS

approved

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Last modified September 23 05:28 EDT 2021. Contains 347609 sequences. (Running on oeis4.)