A336101 Numbers divisible by exactly one odd prime.

3, 5, 6, 7, 9, 10, 11, 12, 13, 14, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 31, 34, 36, 37, 38, 40, 41, 43, 44, 46, 47, 48, 49, 50, 52, 53, 54, 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

Offset

1,1

Comments

Numbers k for which A001221(A000265(k)) = 1. - Antti Karttunen, Jul 08 2020

Numbers whose odd part is a prime power (A246655). - Amiram Eldar, Jul 08 2020

Numbers of the form 2^r * p^q with p an odd prime (A065091), r >= 0, q >= 1. - Bernard Schott, Dec 14 2020

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range[104], PrimePowerQ[#/2^IntegerExponent[#, 2]] &] (* Amiram Eldar, Jul 08 2020 *)

Prog

(PARI) isA336101(n) = (1==omega(n>>valuation(n, 2))); \\ Antti Karttunen, Jul 08 2020

Crossrefs

Cf. A000265, A001221, A246655, A340373 (characteristic function).

Positions of ones in A005087.

Subsequence of A267895.

Subsequences: A007283 (3*2^n), A020714 (5*2^n), A005009 (7*2^n), A005015 (11*2^n), A005029 (13*2^n), A038550 (p*2^n, p odd prime), A065091 (odd primes), A061345 \ {1} (odd prime powers).

Sequence in context: A080943 A363690 A052294 * A267895 A216189 A191916

Adjacent sequences: A336098 A336099 A336100 * A336102 A336103 A336104

Keyword

nonn,easy

Author

Peter Munn, Jul 08 2020

Status

approved