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A164442
Number of binary strings of length n with no substrings equal to 0000 0111 or 1001.
1
13, 21, 33, 51, 79, 122, 188, 289, 444, 682, 1047, 1607, 2466, 3784, 5806, 8908, 13667, 20968, 32169, 49353, 75716, 116161, 178210, 273403, 419444, 643494, 987222, 1514555, 2323567, 3564719, 5468842, 8390067, 12871687, 19747199, 30295319
OFFSET
4,1
FORMULA
G.f.: -x^4*(-13-8*x+x^2+3*x^3+5*x^4+8*x^5) / ( (x-1)*(x^5+x^4+x^3+x^2-1) ). - R. J. Mathar, Jan 19 2011
CROSSREFS
Sequence in context: A164450 A164461 A164499 * A164488 A164436 A164498
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, Aug 14 2009
STATUS
approved