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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A158265 G.f.: A(x) = exp( Sum_{n>=1} 2*sigma(n,n+1)*x^n/n ). 0
1, 2, 11, 74, 697, 8002, 115158, 1949640, 38662510, 872245634, 22150393253, 623661939852, 19296665400632, 650198159192554, 23700604926216759, 928939297013294294, 38956230043045053042, 1740248411222193973416 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Definition: sigma(n,n+1) = Sum_{d|n} d^(n+1): [1,9,82,1057,15626,...].

LINKS

Table of n, a(n) for n=0..17.

EXAMPLE

G.f.: A(x) = 1 + 2*x + 11*x^2 + 74*x^3 + 697*x^4 + 8002*x^5 +...

log(A(x)) = 2*x + 18*x^2/2 + 164*x^3/3 + 2114*x^4/4 + 31252*x^5/5 +...

PROG

(PARI) a(n)=polcoeff(exp(sum(m=1, n, 2*sigma(m, m+1)*x^m/m)+x*O(x^n)), n)

CROSSREFS

Cf. A158095, A023881.

Sequence in context: A058789 A212028 A324445 * A321387 A309146 A198088

Adjacent sequences:  A158262 A158263 A158264 * A158266 A158267 A158268

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Mar 29 2009

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 December 8 02:41 EST 2021. Contains 349590 sequences. (Running on oeis4.)