

A217863


a(n) = phi(lcm(1,2,3,...,n)), where phi is Euler's totient function.


3



1, 1, 2, 4, 16, 16, 96, 192, 576, 576, 5760, 5760, 69120, 69120, 69120, 138240, 2211840, 2211840, 39813120, 39813120, 39813120, 39813120, 875888640, 875888640, 4379443200, 4379443200, 13138329600, 13138329600, 367873228800, 367873228800, 11036196864000
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OFFSET

1,3


COMMENTS

This is a composition f(g(x)). g(x) = lcm(1...x) and f(x) = phi(x), Euler's totient function. The sequence generated is the number of prime congruence classes (prime spokes) for wheel factorization in mod g(x).
First column of A096180.  Eric Desbiaux, Apr 23 2013


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000


FORMULA

a(n) = A000010(A003418(n)).  Omar E. Pol, Nov 25 2012


MATHEMATICA

EulerPhi[Table[LCM @@ Range[n], {n, 35}]] (* T. D. Noe, Oct 16 2012 *)


PROG

(Haskell)
a217863 = a000010 . a003418  Reinhard Zumkeller, Nov 24 2012
(PARI) a(n) = eulerphi(lcm(vector(n, k, k))); \\ Michel Marcus, Aug 25 2015


CROSSREFS

Cf. A000010 (Euler phi), A003418 (LCM).
Sequence in context: A196202 A135569 A210579 * A186108 A131560 A067709
Adjacent sequences: A217860 A217861 A217862 * A217864 A217865 A217866


KEYWORD

nonn,easy


AUTHOR

Joshua S.M. Weiner, Oct 13 2012


STATUS

approved



