login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A238440 Expansion of 1/E(q/E(q)) where E(q) = Product_{n>=1} (1 - q^n). 3
1, 1, 3, 9, 27, 79, 229, 657, 1873, 5304, 14944, 41895, 116947, 325133, 900617, 2486183, 6841490, 18770754, 51358188, 140154540, 381540434, 1036261537, 2808328337, 7594958401, 20499680869, 55227373266, 148520150761, 398726637407, 1068701794158, 2859956501816, 7642086948143, 20391083977989, 54333644617311 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

What does this sequence count?

LINKS

Table of n, a(n) for n=0..32.

FORMULA

G.f.: 1/E(q/E(q)) where E(q) = Product_{n>=1} (1 - q^n).

PROG

(PARI) q = 'q + O('q^66);  Vec( 1/eta(q/eta(q)) )

CROSSREFS

Cf. A109085: G.f. 1/E(q/E(q/E(q/E(q/E(q/E...))))).

Sequence in context: A266497 A291020 A282087 * A269578 A026289 A027129

Adjacent sequences:  A238437 A238438 A238439 * A238441 A238442 A238443

KEYWORD

nonn

AUTHOR

Joerg Arndt, Feb 27 2014

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 October 31 19:00 EDT 2020. Contains 338111 sequences. (Running on oeis4.)