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A085730 Euler's totient function applied to the sequence of prime powers. 3
1, 1, 2, 2, 4, 6, 4, 6, 10, 12, 8, 16, 18, 22, 20, 18, 28, 30, 16, 36, 40, 42, 46, 42, 52, 58, 60, 32, 66, 70, 72, 78, 54, 82, 88, 96, 100, 102, 106, 108, 112, 110, 100, 126, 64, 130, 136, 138, 148, 150, 156, 162, 166, 156, 172, 178, 180, 190, 192, 196, 198, 210 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) = A000010(A000961(n)).

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Prime Power.

Eric Weisstein's World of Mathematics, Totient Function.

FORMULA

a(p^e) = (p-1)*p^(e-1).

a(n) = (A025473(n)-1)*A025473(n)^(A025474(n)-1).

PROG

(Haskell)

a085730 1 = 1

a085730 n = (p - 1) * p ^ (e - 1)

   where p =  a025473 n; e =  a025474 n

-- Reinhard Zumkeller, Feb 16 2012

(PARI) list(lim)=my(v=List(primes(primepi(lim)))); listput(v, 1); for(e=2, log(lim+.5)\log(2), forprime(p=2, (lim+.5)^(1/e), listput(v, p^e))); apply(n->eulerphi(n), vecsort(Vec(v))) \\ Charles R Greathouse IV, Apr 30 2012

CROSSREFS

Cf. A000010, A000961, A025473, A025474, A207193.

Sequence in context: A073256 A166362 A050469 * A232065 A219741 A210603

Adjacent sequences:  A085727 A085728 A085729 * A085731 A085732 A085733

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jul 20 2003

STATUS

approved

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Last modified June 20 09:27 EDT 2019. Contains 324234 sequences. (Running on oeis4.)