A373587 - OEIS

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A373587

Numbers k for which A373149(k) is odd, where A373149 is fully additive with a(2) = 1 and a(p) = prevprime(p) for odd primes p.

2, 5, 6, 7, 8, 11, 13, 15, 17, 18, 19, 20, 21, 23, 24, 28, 29, 31, 32, 33, 37, 39, 41, 43, 44, 45, 47, 50, 51, 52, 53, 54, 57, 59, 60, 61, 63, 67, 68, 69, 70, 71, 72, 73, 76, 79, 80, 83, 84, 87, 89, 92, 93, 96, 97, 98, 99, 101, 103, 107, 109, 110, 111, 112, 113, 116, 117, 123, 124, 125, 127, 128, 129, 130, 131, 132

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OFFSET

1,1

COMMENTS

Numbers such that the number of their prime factors (with multiplicity, A001222) and their 3-adic valuation (A007949) have different parity.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

FORMULA

{k | A001222(k)+A007949(k) == 1 (mod 2)}.

PROG

(PARI) isA373587(n) = !A373585(n);

CROSSREFS