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A267895 Numbers whose number of odd divisors is prime. 1
3, 5, 6, 7, 9, 10, 11, 12, 13, 14, 17, 18, 19, 20, 22, 23, 24, 25, 26, 28, 29, 31, 34, 36, 37, 38, 40, 41, 43, 44, 46, 47, 48, 49, 50, 52, 53, 56, 58, 59, 61, 62, 67, 68, 71, 72, 73, 74, 76, 79, 80, 81, 82, 83, 86, 88, 89, 92, 94, 96, 97, 98, 100, 101, 103, 104, 106, 107, 109 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All odd primes are in the sequence.

LINKS

Table of n, a(n) for n=1..69.

EXAMPLE

The divisors of 36 are 1, 2, 3, 4, 6, 9, 12, 18, 36. The odd divisors of 36 are 1, 3, 9. There are 3 odd divisors of 36 and 3 is prime, so 36 is in the sequence.

PROG

(PARI) isok(n) = isprime(sumdiv(n, d, (d%2))); \\ Michel Marcus, Apr 04 2016

CROSSREFS

Complement of A267894.

Cf. A000040, A001227, A028982, A028983, A038550, A065091, A072502, A266531, A267696, A267697.

Sequence in context: A277727 A080943 A052294 * A216189 A191916 A254614

Adjacent sequences:  A267892 A267893 A267894 * A267896 A267897 A267898

KEYWORD

nonn

AUTHOR

Omar E. Pol, Apr 04 2016

STATUS

approved

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Last modified December 10 20:23 EST 2019. Contains 329909 sequences. (Running on oeis4.)