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A049200 Euler totient function phi applied to the n-th squarefree number. 3
1, 1, 2, 4, 2, 6, 4, 10, 12, 6, 8, 16, 18, 12, 10, 22, 12, 28, 8, 30, 20, 16, 24, 36, 18, 24, 40, 12, 42, 22, 46, 32, 52, 40, 36, 28, 58, 60, 30, 48, 20, 66, 44, 24, 70, 72, 36, 60, 24, 78, 40, 82, 64, 42, 56, 88, 72, 60, 46, 72, 96, 100, 32, 102, 48, 52, 106, 108, 40, 72 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) = product(A265668(n,k) + 1: k = 1..A001221(n)). - Reinhard Zumkeller, Dec 13 2015

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A000010(A005117(n)).

EXAMPLE

The 12th squarefree number is 17 and phi(17) is 16, so a(12)=16.

MAPLE

map(numtheory:-phi, select(numtheory:-issqrfree, [$1..1000])); # Robert Israel, Jul 12 2015

MATHEMATICA

EulerPhi[ x ] if Abs[ MoebiusMu[ x ] ]=1

EulerPhi/@Select[Range[200], SquareFreeQ] (* Harvey P. Dale, Jan 13 2015 *)

PROG

(PARI) lista(nn) = {for(n=1, nn, if (issquarefree(n), print1(eulerphi(n), ", "))); } \\ Michel Marcus, Jul 12 2015

(MAGMA) [EulerPhi(n): n in [1..300] | IsSquarefree(n)]; // Vincenzo Librandi, Jul 13 2015

(Haskell)

a049200 1 = 1

a049200 n = product $ map (subtract 1) $ a265668_row n

-- Reinhard Zumkeller, Dec 13 2015

CROSSREFS

Cf. A000010, A005117, A013929.

Cf. A265668, A001221.

Sequence in context: A212012 A322071 A176342 * A164701 A198540 A216369

Adjacent sequences:  A049197 A049198 A049199 * A049201 A049202 A049203

KEYWORD

nonn

AUTHOR

Labos Elemer

STATUS

approved

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Last modified April 22 14:23 EDT 2019. Contains 322349 sequences. (Running on oeis4.)