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A097041 Expansion of (1+x)/(1-x^2-9x^3). 0
1, 1, 1, 10, 10, 19, 100, 109, 271, 1009, 1252, 3448, 10333, 14716, 41365, 107713, 173809, 479998, 1143226, 2044279, 5463208, 12333313, 23861719, 61502185, 134861536, 276257656, 688381201, 1490011480, 3174700105, 7685442289 (list; graph; refs; listen; history; internal format)
OFFSET

0,4

FORMULA

a(n)=a(n-2)+9a(n-3); a(n)=sum{k=0..floor(n/2), binomial(floor((n-k)/2), k)9^k }.

CROSSREFS

Cf. A015445.

Sequence in context: A047879 A168416 A141324 * A205724 A040091 A168461

Adjacent sequences:  A097038 A097039 A097040 * A097042 A097043 A097044

KEYWORD

easy,nonn

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Jul 20 2004

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Last modified February 17 08:44 EST 2012. Contains 205998 sequences.