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A164423
Number of binary strings of length n with no substrings equal to 0000 0010 or 1100.
1
13, 21, 35, 59, 100, 171, 292, 497, 845, 1436, 2440, 4147, 7050, 11986, 20378, 34645, 58899, 100131, 170227, 289394, 491985, 836402, 1421931, 2417363, 4109652, 6986636, 11877667, 20192690, 34328690, 58360674, 99216379, 168673341
OFFSET
4,1
FORMULA
G.f.: -x^4*(13+8*x+x^2+3*x^3+6*x^4+12*x^5+8*x^6) / ( -1+x+x^2+x^6+x^7 ). - R. J. Mathar, Dec 01 2011
CROSSREFS
Sequence in context: A164465 A164471 A164477 * A164422 A164500 A164430
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, Aug 14 2009
STATUS
approved