A164489 Number of binary strings of length n with no substrings equal to 0001 1011 or 1100.

13, 20, 30, 45, 68, 103, 156, 236, 356, 536, 806, 1211, 1819, 2732, 4103, 6162, 9254, 13897, 20869, 31338, 47058, 70663, 106108, 159332, 239253, 359262, 539467, 810062, 1216386, 1826520, 2742694, 4118416, 6184193, 9286153, 13944040, 20938299

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,-1,1,1,-1).

Formula

G.f.: -x^4*(-13+6*x+10*x^2+2*x^3-11*x^4-4*x^5+8*x^6) / ( (x-1)*(x^6-x^4+x^2+x-1) ). - R. J. Mathar, Jan 19 2011

Crossrefs

Sequence in context: A164475 A164483 A164468 * A164464 A164467 A164505

Adjacent sequences: A164486 A164487 A164488 * A164490 A164491 A164492

Keyword

nonn,easy

Author

R. H. Hardin, Aug 14 2009

Status

approved