A164439 Number of binary strings of length n with no substrings equal to 0000 0110 or 1001.

13, 21, 34, 56, 92, 151, 247, 405, 663, 1087, 1780, 2918, 4779, 7833, 12830, 21027, 34444, 56446, 92469, 151528, 248242, 406776, 666426, 1091993, 1789068, 2931473, 4802866, 7869607, 12893569, 21126181, 34613470, 56713903, 92921589, 152250422

Offset

4,1

Links

R. H. Hardin, Table of n, a(n) for n=4..500

Index entries for linear recurrences with constant coefficients, signature (1,1,-1,2,-1,1).

Formula

G.f.: -x^4*(13+8*x+14*x^3-3*x^4+8*x^5) / ( -1+x+x^2-x^3+2*x^4-x^5+x^6 ). - R. J. Mathar, Jan 19 2011

Mathematica

LinearRecurrence[{1, 1, -1, 2, -1, 1}, {13, 21, 34, 56, 92, 151}, 40] (* Harvey P. Dale, Dec 13 2014 *)

Crossrefs

Sequence in context: A164497 A164503 A164449 * A164492 A164451 A164432

Adjacent sequences: A164436 A164437 A164438 * A164440 A164441 A164442

Keyword

nonn,easy

Author

R. H. Hardin, Aug 14 2009

Status

approved