A164451 Number of binary strings of length n with no substrings equal to 0001 0010 or 1100.

13, 21, 34, 56, 93, 156, 261, 437, 731, 1223, 2046, 3424, 5730, 9590, 16050, 26862, 44957, 75242, 125928, 210759, 352736, 590356, 988048, 1653645, 2767620, 4632023, 7752378, 12974756, 21715181, 36343581, 60826381, 101801984, 170380742

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 (2,0,-1,0,0,1,-1).

Formula

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

Mathematica

LinearRecurrence[{2, 0, -1, 0, 0, 1, -1}, {13, 21, 34, 56, 93, 156, 261}, 40] (* Harvey P. Dale, Dec 30 2017 *)

Crossrefs

Sequence in context: A164449 A164439 A164492 * A164432 A034292 A163113

Adjacent sequences: A164448 A164449 A164450 * A164452 A164453 A164454

Keyword

nonn,easy

Author

R. H. Hardin, Aug 14 2009

Status

approved