A181239 Number of n X 4 binary matrices with no 2 X 2 circuit having pattern 0101 in any orientation.

16, 178, 2066, 23858, 275690, 3185462, 36806846, 425288998, 4914052362, 56780001474, 656071271338, 7580653428086, 87591560417790, 1012087088416198, 11694280472399626, 135122952690874754, 1561294205914890890

Offset: 1

Author

R. H. Hardin, Oct 10 2010

Keywords

• nonn

Comments

Column 4 of A181245.

Links

• R. H. Hardin, Table of n, a(n) for n=1..200

Crossrefs

Cf. A181245.

Formula

Empirical: a(n) = 10*a(n-1) + 20*a(n-2) - 21*a(n-3) - 30*a(n-4) + 8*a(n-5).

Empirical g.f.: 2*x*(8 + 9*x - 17*x^2 - 13*x^3 + 4*x^4) / (1 - 10*x - 20*x^2 + 21*x^3 + 30*x^4 - 8*x^5). - Colin Barker, Mar 26 2018