A238367 Even numbers n such that n is not divisible by 2^d where d is the number of distinct odd prime factors of n.

30, 42, 66, 70, 78, 90, 102, 110, 114, 126, 130, 138, 150, 154, 170, 174, 182, 186, 190, 198, 210, 222, 230, 234, 238, 246, 258, 266, 270, 282, 286, 290, 294, 306, 310, 318, 322, 330, 342, 350, 354, 366, 370, 374, 378, 390, 402, 406, 410, 414, 418, 420, 426, 430, 434, 438, 442, 450, 462, 470, 474, 490, 494, 498

Offset

1,1

Comments

Inspired by comment by Don Reble in A072995.

2*A061346 = A238367 with the exceptions of 420, 660, 780, 924, 1020, 1092, 1140, 1260, ... .

Links

Table of n, a(n) for n=1..64.

Example

30 is in the sequence because the odd primes that divide 30 are 3 and 5, but 2^2 does not divide 30.

Mathematica

Select[2 Range[250], Mod[#, 2^(PrimeNu[#] - 1)] != 0 &]

Crossrefs

Cf. A072995.

Sequence in context: A136152 A244066 A090815 * A225228 A336568 A350352

Adjacent sequences: A238364 A238365 A238366 * A238368 A238369 A238370

Keyword

nonn

Author

Robert G. Wilson v, Feb 25 2014

Status

approved