login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A113706 Expansion of Product_{k>0} (1-x^(3k))/(1-x^(3k-2)). 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 (list; graph; refs; listen; history; text; internal format)
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: A141571 A164067 A305490 * A279952 A054845 A317991

Adjacent sequences:  A113703 A113704 A113705 * A113707 A113708 A113709

KEYWORD

sign

AUTHOR

Michael Somos, Nov 06 2005

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 17 16:38 EDT 2019. Contains 325107 sequences. (Running on oeis4.)