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

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A159553 a(n) = sum{k=0 to n} binomial(n,k) * GCD(n,k). 3
2, 6, 12, 28, 40, 144, 140, 536, 864, 2560, 2068, 12720, 8216, 45192, 78660, 182832, 131104, 933984, 524324, 3698240, 4890648, 13345816, 8388652, 67390464, 60129600, 225470544, 279938160, 1032462256, 536870968, 5018059200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For the purpose of this sequence, GCD(n,0) = n, for all positive integers n.

a(n) is a multiple of n, for all nonnegative integers n.

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..3317

FORMULA

a(n) = A159068(n) + n.

a(n) = 2^n * sum_{d|n} (phi(d)/d) * sum_{k=1..d} (-1)^(k*n/d)*cos(k*Pi/d)^n.

MAPLE

A159553 := proc(n) add(binomial(n, k)*gcd(k, n), k=0..n) ; end: seq(A159553(n), n=1..40) ; # From R. J. Mathar, Apr 29 2009

MATHEMATICA

Table[Sum[Binomial[n, k] GCD[n, k], {k, 0, n}], {n, 30}] (* Michael De Vlieger, Oct 30 2017 *)

CROSSREFS

Cf. A159068, A159554.

Sequence in context: A185961 A290674 A290419 * A222970 A112510 A284449

Adjacent sequences:  A159550 A159551 A159552 * A159554 A159555 A159556

KEYWORD

nonn

AUTHOR

Leroy Quet, Apr 14 2009

EXTENSIONS

Extended by R. J. Mathar, Apr 29 2009

Ambiguous term a(0) removed by Max Alekseyev, Jan 09 2015

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified November 18 02:54 EST 2017. Contains 294840 sequences.