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A353810
a(n) = 1 if sigma(n) has an odd number of prime factors (with multiplicity), and 0 otherwise. Here sigma is the sum of divisors function.
2
0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1
OFFSET
1
COMMENTS
Parity of A058063(n), bigomega(sigma(n)).
FORMULA
MATHEMATICA
a[n_] := If[OddQ[PrimeOmega[DivisorSigma[1, n]]], 1, 0]; Array[a, 100] (* Amiram Eldar, May 13 2022 *)
PROG
(PARI) A353810(n) = (bigomega(sigma(n))%2);
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 13 2022
STATUS
approved