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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. 2
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 (list; graph; refs; listen; history; text; internal format)
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 A093599 A007304

Adjacent sequences:  A238364 A238365 A238366 * A238368 A238369 A238370

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Feb 25 2014

STATUS

approved

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Last modified April 5 13:02 EDT 2020. Contains 333241 sequences. (Running on oeis4.)