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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A306898 a(n) = Sum_{d|n} 2^d*phi(2*n/d). 4
2, 8, 12, 32, 40, 96, 140, 320, 540, 1120, 2068, 4320, 8216, 16688, 32880, 66176, 131104, 263376, 524324, 1050880, 2097480, 4198480, 8388652, 16786368, 33554600, 67125344, 134218836, 268468928, 536870968, 1073809920, 2147483708, 4295099648, 8589938808, 17180131456, 34359739120, 68720011776 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..3321

Dennis S. Bernstein, Omran Kouba, Counting Colorful Necklaces and Bracelets in Three Colors, arXiv:1901.10703 [math.CO], 2019.

MAPLE

See A306888.

MATHEMATICA

Table[DivisorSum[n, 2^# *EulerPhi[2 n/#] &], {n, 36}] (* Michael De Vlieger, Mar 18 2019 *)

PROG

(PARI) a(n) = sumdiv(n, d, 2^d*eulerphi(2*n/d)); \\ Michel Marcus, Mar 16 2019

CROSSREFS

Cf. A306888, A306896.

Sequence in context: A047174 A048074 A126775 * A069185 A037197 A125712

Adjacent sequences:  A306895 A306896 A306897 * A306899 A306900 A306901

KEYWORD

nonn

AUTHOR

Michael De Vlieger and N. J. A. Sloane, Mar 15 2019

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 13 23:14 EST 2019. Contains 329974 sequences. (Running on oeis4.)