A353499 - OEIS

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A353499

a(n) = 1 if n is a squarefree number for which the 2-adic valuation of phi(n) does not exceed the 2-adic valuation of n-1, otherwise 0.

0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0

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OFFSET

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for characteristic functions

FORMULA

a(n) = A008966(n) * A353498(n).

PROG

(PARI) A353499(n) = ((n>1)&&issquarefree(n)&&(valuation(eulerphi(n), 2)<=valuation(n-1, 2)));

CROSSREFS

Characteristic function of A339817.

Cf. A000010, A008966, A007814, A053574, A353498.