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A102466 Numbers such that the number of divisors is the sum of numbers of prime factors with and without repetitions. 4
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 21, 22, 23, 25, 26, 27, 29, 31, 32, 33, 34, 35, 37, 38, 39, 41, 43, 46, 47, 49, 51, 53, 55, 57, 58, 59, 61, 62, 64, 65, 67, 69, 71, 73, 74, 77, 79, 81, 82, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 101, 103, 106, 107, 109 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

A000005(a(n)) = A001221(a(n)) + A001222(a(n)); prime powers are a subsequence (A000961); complement of A102467; not the same as A085156.

Equals { n | omega(n)=1 or Omega(n)=2 }, that is, these are exactly the prime powers (>1) and semiprimes. - M. F. Hasler (Maximilian.Hasler(AT)gmail.com), Jan 14 2008

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

PROG

(Sage)

def is_A102466(n) :

    return bool(sloane.A001221(n) == 1 or sloane.A001222(n) == 2)

def A102466_list(n) :

    return [k for k in (1..n) if is_A102466(k)]

A102466_list(109)  # Peter Luschny, Feb 08 2012

CROSSREFS

Cf. A135767.

Sequence in context: A072774 A062770 A085156 * A084176 A059389 A191328

Adjacent sequences:  A102463 A102464 A102465 * A102467 A102468 A102469

KEYWORD

nonn,changed

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jan 09 2005

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Last modified February 12 18:02 EST 2012. Contains 205432 sequences.