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!)
A092502 First derivative of cyclotomic(n,x) evaluated at x=1. 1
1, 1, 3, 2, 10, 1, 21, 4, 9, 2, 55, 2, 78, 3, 4, 8, 136, 3, 171, 4, 6, 5, 253, 4, 50, 6, 27, 6, 406, 4, 465, 16, 10, 8, 12, 6, 666, 9, 12, 8, 820, 6, 903, 10, 12, 11, 1081, 8, 147, 10, 16, 12, 1378, 9, 20, 12, 18, 14, 1711, 8, 1830, 15, 18, 32, 24, 10, 2211, 16, 22, 12, 2485, 12 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Indranil Ghosh, Table of n, a(n) for n = 1..5000

FORMULA

a(n) = (phi(n)/2)*Product_{d|n} d^moebius(n/d), n>1.

MATHEMATICA

Table[If[n>1, (EulerPhi[n]/2) * Product[d^MoebiusMu[n/d], {d, Divisors[n]}], 1], {n , 1, 72}] (* Indranil Ghosh, Mar 16 2017 *)

PROG

(PARI) a(n) = {my(r = 1); fordiv(n, d, r*=d^moebius(n/d)); r};

for(n=1, 72, print1(if(n==1, 1, (eulerphi(n)/2) * a(n)), ", ")) \\ Indranil Ghosh, Mar 16 2017

CROSSREFS

Cf. A020500.

Sequence in context: A234748 A156528 A234744 * A292923 A135515 A114486

Adjacent sequences:  A092499 A092500 A092501 * A092503 A092504 A092505

KEYWORD

nonn

AUTHOR

Vladeta Jovovic, Apr 05 2004

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 February 21 02:02 EST 2020. Contains 332086 sequences. (Running on oeis4.)