A340371 - OEIS

A340371

a(n) = 1 if the odd part of n is noncomposite, 0 otherwise.

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

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OFFSET

COMMENTS

a(n) = 1 if n is of the form 2^i * p^j, for some odd prime p, with i >= 0, 0 <= j <= 1, and 0 otherwise.

LINKS

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

Index entries for characteristic functions

FORMULA

a(n) = A080339(A000265(n)).

For n > 1, a(n) = abs(A304438(n)).

MATHEMATICA

A340371[n_] := If[# == 1, 1, Boole[PrimeQ[#]]] & [n/2^IntegerExponent[n, 2]];