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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.
2
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
OFFSET
1
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.
Sequence in context: A374130 A374466 A283991 * A359372 A327861 A131929
KEYWORD
nonn
AUTHOR
Antti Karttunen, Apr 22 2022
STATUS
approved