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A373585
a(n) = 1 if A373149(n) is even, otherwise 0, where A373149 is fully additive with a(2) = 1 and a(p) = prevprime(p) for odd primes p.
7
1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1
OFFSET
1
FORMULA
a(n) = A059841(A373149(n)).
a(n) = A059841(A001222(n) - A007949(n)).
PROG
(PARI)
A373149(n) = { my(f = factor(n)); sum(i = 1, #f~, f[i, 2]*if(2==f[i, 1], 1, precprime(f[i, 1] - 1))); };
A373585(n) = !(A373149(n)%2);
(PARI) A373585(n) = !((bigomega(n)-valuation(n, 3))%2);
CROSSREFS
Characteristic function of A373586, whose complement A373587 gives the positions of 0's.
Sequence in context: A145377 A374113 A374107 * A246260 A275973 A218173
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 12 2024
STATUS
approved