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A353670
a(n) = 1 if the odd part of n is a prime, otherwise 0.
3
0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 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, 0, 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, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0
OFFSET
1
FORMULA
a(n) = A010051(A000265(n)).
For n <> 2, a(n) = A010051(n) + A353671(n).
For all n >= 1, a(n) <= A353627(n), a(n) <= A329697(n) and a(n) <= A331410(n).
a(n) = [2 == A001227(n)], where [ ] is the Iverson bracket.
PROG
(PARI) A353670(n) = isprime(n>>valuation(n, 2));
CROSSREFS
Characteristic function of A038550.
Sequence in context: A324903 A011656 A295309 * A252744 A340373 A043545
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 03 2022
STATUS
approved