A304004 Number of n X 2 0..1 arrays with every element unequal to 0, 2, 3 or 5 king-move adjacent elements, with upper left element zero.
1, 4, 7, 13, 26, 49, 99, 194, 387, 773, 1538, 3081, 6147, 12298, 24587, 49157, 98330, 196609, 393251, 786450, 1572883, 3145797, 6291442, 12583033, 25165827, 50331738, 100663451, 201326533, 402653578, 805306225, 1610613155, 3221225698
Offset: 1
Keywords
Examples
Some solutions for n=5 ..0..0. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..0. .0..1. .0..1 ..1..1. .0..1. .1..0. .0..1. .1..0. .1..0. .1..0. .0..0. .1..0. .0..1 ..1..1. .0..1. .0..1. .1..0. .0..1. .1..0. .0..1. .0..0. .1..0. .1..0 ..1..1. .0..1. .0..1. .1..0. .0..1. .1..0. .1..0. .0..0. .0..1. .0..1 ..0..0. .0..1. .0..1. .1..0. .1..0. .0..1. .0..1. .0..0. .0..1. .0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A304010.
Formula
Empirical: a(n) = a(n-1) +3*a(n-2) -4*a(n-4) for n > 5.
Comments