A272960 Number of nX3 0..1 arrays with exactly n+3-1 having value 1 and no three 1s forming an isosceles right triangle.

1, 1, 0, 1, 9, 6, 16, 66, 95, 177, 493, 1153, 2238, 5011, 11642, 25096, 55321, 123997, 273017, 600569, 1336351, 2963793, 6536040, 14463667, 32057919, 70930270, 156916549, 347367018, 768795181, 1701248904, 3765540655, 8334284668

Offset

1,5

Comments

Column 3 of A272965.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) -3*a(n-2) +4*a(n-3) -6*a(n-5) +3*a(n-6) -6*a(n-7) -16*a(n-8) +44*a(n-9) -14*a(n-10) -42*a(n-11) +65*a(n-12) -56*a(n-13) +52*a(n-14) -8*a(n-15) -65*a(n-16) +63*a(n-17) -43*a(n-18) +64*a(n-19) -6*a(n-20) -119*a(n-21) +122*a(n-22) +42*a(n-23) -93*a(n-24) +16*a(n-25) +20*a(n-26) -6*a(n-27) -8*a(n-28) -2*a(n-30) -2*a(n-31) +4*a(n-32)

Example

All solutions for n=6
..1..1..0. .0..1..1. .1..1..0. .1..0..1. .1..1..1. .0..1..1
..0..0..1. .1..0..0. .0..0..1. .1..0..1. .0..0..0. .1..0..0
..1..0..0. .0..0..1. .0..0..1. .0..0..0. .0..1..0. .1..0..0
..1..0..0. .0..0..1. .0..0..1. .0..0..0. .0..1..0. .1..0..0
..0..0..1. .1..0..0. .0..0..1. .1..0..1. .0..0..0. .1..0..0
..1..1..0. .0..1..1. .1..1..0. .1..0..1. .1..1..1. .0..1..1

Crossrefs

Cf. A272965.

Sequence in context: A180856 A166520 A102648 * A040074 A088999 A073782

Adjacent sequences: A272957 A272958 A272959 * A272961 A272962 A272963

Keyword

nonn

Author

R. H. Hardin, May 11 2016

Status

approved