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A117997 Sum_{d|n} a(d) = n for n=3^m (m>=0) and for other n the sum is zero; i.e., the Moebius transform of [1,0,3,0,0,0,0,0,9,0,...]. 0
1, -1, 2, 0, -1, -2, -1, 0, 6, 1, -1, 0, -1, 1, -2, 0, -1, -6, -1, 0, -2, 1, -1, 0, 0, 1, 18, 0, -1, 2, -1, 0, -2, 1, 1, 0, -1, 1, -2, 0, -1, 2, -1, 0, -6, 1, -1, 0, 0, 0, -2, 0, -1, -18, 1, 0, -2, 1, -1, 0, -1, 1, -6, 0, 1, 2, -1, 0, -2, -1, -1, 0, -1, 1, 0, 0, 1, 2, -1, 0, 54, 1, -1, 0, 1, 1, -2, 0, -1, 6, 1, 0, -2, 1, 1, 0, -1, 0, -6, 0, -1, 2, -1, 0, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..104.

FORMULA

G.f.: x = Sum_{n>=1} a(n)/n*log(1 + x^n + x^(2n)).

1=sum(k=1,n,a(k)*g(n/k)) where g(x)=floor(x)-3*floor(x/3) [From Benoit Cloitre, Nov 11 2010]

PROG

(PARI) {a(n)=if(n==1, 1, -n*polcoeff(x+sum(k=1, n-1, a(k)/k*subst(log(1+x+x^2+x*O(x^n)), x, x^k+x*O(x^n))), n))}

CROSSREFS

Sequence in context: A092928 A219026 A085097 * A079684 A033761 A033805

Adjacent sequences:  A117994 A117995 A117996 * A117998 A117999 A118000

KEYWORD

sign

AUTHOR

Paul D. Hanna, Apr 08 2006

STATUS

approved

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Last modified April 23 17:46 EDT 2014. Contains 240946 sequences.