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A272954 Number of nX4 0..1 arrays with exactly n+4-2 having value 1 and no three 1s forming an isosceles right triangle. 1
4, 21, 24, 60, 210, 637, 1840, 5792, 18556, 54034, 160246, 499140, 1501706, 4627363, 13954490, 43064736, 131174878, 399170874, 1222825766, 3739040310, 11456400210, 35068696769, 107362206600, 329271410590, 1009129910706, 3096269613087 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A272958.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..110

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A272958.

Sequence in context: A138228 A303722 A305225 * A133784 A041821 A042429

Adjacent sequences: A272951 A272952 A272953 * A272955 A272956 A272957

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 11 2016

STATUS

approved

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Last modified February 7 02:40 EST 2023. Contains 360111 sequences. (Running on oeis4.)