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A163377 a(n) = tau(phi(tau(n))). 2
1, 1, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 3, 1, 2, 1, 2, 2, 2, 1, 3, 2, 2, 2, 2, 1, 3, 1, 2, 2, 2, 2, 4, 1, 2, 2, 3, 1, 3, 1, 2, 2, 2, 1, 3, 2, 2, 2, 2, 1, 3, 2, 3, 2, 2, 1, 3, 1, 2, 2, 4, 2, 3, 1, 2, 2, 3, 1, 3, 1, 2, 2, 2, 2, 3, 1, 3, 3, 2, 1, 3, 2, 2, 2, 3, 1, 3, 2, 2, 2, 2, 2, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = A000005(A000010(A000005(n))) = A000005(A163109(n)) = A062821(A000005(n)).

MATHEMATICA

DivisorSigma[0, EulerPhi[DivisorSigma[0, Range[100]]]] (* G. C. Greubel, Dec 20 2016 *)

PROG

(PARI) vector(100, n, numdiv(eulerphi(numdiv(n)))) \\ G. C. Greubel, Dec 20 2016

CROSSREFS

Cf. A000005, A000010, A062821, A163109.

Sequence in context: A036430 A323305 A322794 * A290085 A322867 A163109

Adjacent sequences:  A163374 A163375 A163376 * A163378 A163379 A163380

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Jul 25 2009

STATUS

approved

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Last modified October 1 00:23 EDT 2020. Contains 337440 sequences. (Running on oeis4.)