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Search: id:A128695
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A128695 Number of compositions of n with parts in N which avoid the pattern 111. +0
1
1, 1, 2, 3, 7, 13, 24, 46, 89, 170, 324, 618, 1183, 2260, 4318, 8249, 15765, 30123, 57556, 109973, 210137, 401525, 767216, 1465963, 2801115, 5352275, 10226930, 19541236, 37338699, 71345449, 136324309, 260483548, 497722578, 951030367 (list; graph; listen)
OFFSET

0,3

LINKS

S. Heubach and T. Mansour, Enumeration of 3-letter patterns in combinations

FORMULA

G.f.: 1/(1-sum(i>=1, X^i*(1+X^i)/(1+X^i*(1+X^i)) ) )

CROSSREFS

Sequence in context: A088175 A091440 A075058 this_sequence A024504 A088172 A048573

Adjacent sequences: A128692 A128693 A128694 this_sequence A128696 A128697 A128698

KEYWORD

nonn

AUTHOR

Ralf Stephan, May 08 2007

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.


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