A113706 Expansion of Product_{k>0} (1-x^(3k))/(1-x^(3k-2)).

1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, -1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, -1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, -1, 1, 1, -1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, -1, 0, 0, 0, 1, 1, 0, 1, 0, -1, 1, 1, -1, 0, 1, -1, 0, 2, 0, -1, 1, 0, -1, 1, 1, 0, 1, 0, -1, 1

Offset

0,93

Comments

|a(n)|<2 if n<92, |a(n)|<3 if n<204.

Links

Seiichi Manyama, Table of n, a(n) for n = 0..10000

Formula

Euler transform of period 3 sequence [1, 0, -1, ...].

G.f.: Product_{k>0} (1-x^(3k))/(1-x^(3k-2)).

Prog

(PARI) {a(n)=if(n<0, 0, polcoeff( prod(k=1, n, (1-x^k)^([1, -1, 0][k%3+1]), 1+x*O(x^n)), n))}

Crossrefs

Cf. A143240.

Sequence in context: A164067 A353918 A305490 * A279952 A054845 A317991

Adjacent sequences: A113703 A113704 A113705 * A113707 A113708 A113709

Keyword

sign

Author

Michael Somos, Nov 06 2005

Status

approved