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!)
A179307 a(n) = Sum_{d|n} C(n,d)*sigma(d)*sigma(n/d). 1
1, 9, 16, 89, 36, 504, 64, 2193, 1474, 5544, 144, 56024, 196, 84912, 83376, 674257, 324, 2833128, 400, 10842624, 3764224, 25404696, 576, 283622136, 1913486, 436839984, 243868120, 2955876880, 900, 13385040624, 1024, 57008721777 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..32.

FORMULA

Logarithmic derivative of A179306.

PROG

(PARI) {a(n)=sumdiv(n, d, binomial(n, d)*sigma(d)*sigma(n/d))}

CROSSREFS

Cf. A179306.

Sequence in context: A267763 A340164 A308248 * A014720 A138238 A177171

Adjacent sequences:  A179304 A179305 A179306 * A179308 A179309 A179310

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jul 10 2010

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 4 15:36 EST 2021. Contains 349526 sequences. (Running on oeis4.)