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!)
A280424 G.f.: Product_{k>=1} (1 + x^k) / (1 - x^(k*(k+1))). 1
1, 1, 2, 3, 4, 6, 9, 12, 16, 22, 28, 37, 49, 62, 79, 101, 125, 157, 196, 241, 297, 365, 443, 539, 654, 787, 947, 1137, 1355, 1616, 1923, 2276, 2693, 3179, 3737, 4391, 5149, 6018, 7027, 8191, 9521, 11057, 12822, 14831, 17140, 19779, 22777, 26206, 30110, 34534 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..49.

FORMULA

a(n) ~ exp(sqrt(n/3)*Pi + 3^(1/4) * Zeta(3/2) * n^(1/4) / sqrt(2) - 3*Zeta(3/2)^2 / (16*Pi)) / (16 * 3^(3/4) * n^(5/4)).

MATHEMATICA

nmax=60; CoefficientList[Series[Product[(1+x^k)/(1-x^(k*(k+1))), {k, 1, nmax}], {x, 0, nmax}], x]

CROSSREFS

Cf. A007294, A000009, A280422.

Sequence in context: A305630 A271147 A069907 * A083365 A001935 A286141

Adjacent sequences:  A280421 A280422 A280423 * A280425 A280426 A280427

KEYWORD

nonn

AUTHOR

Vaclav Kotesovec, Jan 02 2017

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 August 15 16:02 EDT 2020. Contains 336505 sequences. (Running on oeis4.)