A133523 Number of length n binary sequences with at most 2 of every adjacent 6 bits set.

1, 2, 4, 7, 11, 16, 22, 34, 54, 86, 136, 212, 324, 498, 772, 1202, 1873, 2915, 4524, 7012, 10873, 16877, 26213, 40716, 63227, 98154, 152353, 236493, 367150, 570034, 885032, 1374048, 2133185, 3311680, 5141292, 7981842, 12391897, 19238551, 29867908

Offset: 0

Author

R. H. Hardin, Dec 24 2007

Keywords

• nonn

Links

• R. H. Hardin, Table of n, a(n) for n = 0..215

Formula

Empirical: a(n) = a(n-1) + a(n-3) + 2*a(n-6) - 2*a(n-9) - a(n-10) - a(n-12) + a(n-15). - R. H. Hardin, Apr 29 2012.

Empirical g.f.: (1 + x + 2*x^2 + 2*x^3 + 2*x^4 + x^5 - 3*x^6 - 3*x^7 - 4*x^8 - 2*x^9 - x^10 + x^12 + x^13 + x^14) / ((1 - x)*(1 + x + x^2)*(1 - x - x^4 - 2*x^6 - x^7 + x^12)). - Colin Barker, Feb 22 2018