A304947 Number of nX3 0..1 arrays with every element unequal to 0, 2, 3, 5 or 7 king-move adjacent elements, with upper left element zero.

1, 7, 13, 21, 29, 58, 120, 250, 515, 1100, 2302, 4973, 10539, 22512, 48417, 103240, 222483, 476629, 1023567, 2201683, 4721852, 10159934, 21815950, 46884155, 100796318, 216507106, 465528729, 1000276465, 2149938118, 4621346273

Offset

1,2

Comments

Column 3 of A304952.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +2*a(n-2) -9*a(n-3) -8*a(n-4) +27*a(n-5) -8*a(n-6) -22*a(n-7) +29*a(n-8) -9*a(n-9) -22*a(n-10) +9*a(n-11) +44*a(n-12) -33*a(n-13) -10*a(n-14) +30*a(n-15) -32*a(n-16) +4*a(n-17) +6*a(n-18) for n>19

Example

Some solutions for n=5
..0..0..0. .0..1..0. .0..0..0. .0..1..0. .0..0..0. .0..0..0. .0..1..0
..1..1..1. .1..0..1. .0..0..0. .1..1..1. .0..0..0. .0..0..0. .1..0..1
..1..1..1. .1..1..0. .0..0..0. .0..0..0. .0..0..0. .1..1..1. .0..1..1
..1..1..1. .1..0..1. .1..1..1. .0..0..0. .0..0..0. .1..1..1. .1..0..1
..0..0..0. .0..1..0. .0..1..0. .0..0..0. .1..1..1. .1..1..1. .0..1..0

Crossrefs

Cf. A304952.

Sequence in context: A157971 A135275 A304005 * A013652 A099988 A076947

Adjacent sequences: A304944 A304945 A304946 * A304948 A304949 A304950

Keyword

nonn

Author

R. H. Hardin, May 22 2018

Status

approved