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A164425
Number of binary strings of length n with no substrings equal to 0000 0010 or 1111.
1
13, 22, 37, 62, 105, 177, 298, 502, 846, 1426, 2403, 4049, 6823, 11498, 19376, 32651, 55021, 92718, 156243, 263291, 443681, 747663, 1259915, 2123130, 3577765, 6029024, 10159732, 17120542, 28850461, 48616982, 81926280, 138057015, 232645000
OFFSET
4,1
FORMULA
G.f.: -x^4*(13+9*x+15*x^2+12*x^3+8*x^4) / ( -1+x+x^3+x^4+x^5 ). - R. J. Mathar, Dec 01 2011
CROSSREFS
Sequence in context: A164506 A164440 A164435 * A164501 A164495 A164427
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, Aug 14 2009
STATUS
approved