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A112887 Semiprime(n) - composite(n). 0
0, 0, 1, 1, 4, 3, 7, 7, 9, 8, 13, 13, 13, 14, 14, 20, 22, 23, 25, 25, 25, 28, 30, 33, 36, 38, 42, 43, 42, 42, 45, 45, 45, 45, 55, 59, 61, 63, 63, 64, 64, 63, 67, 70, 70, 76, 76, 75, 76, 76, 83, 84, 84, 85, 89, 91, 97, 97, 101, 101, 102, 108, 114, 114, 113, 114, 114, 116, 119 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

The first occurrence where the sequence has k similar terms: 4, 0, 13, 45, 857, 523807, 119, ...

LINKS

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

MATHEMATICA

Select[ Range@225, Plus @@ Last /@ FactorInteger@# == 2 &] - Select[ Range[2, 102], !PrimeQ[ # ] &]

CROSSREFS

Cf. A002808, A001358.

Sequence in context: A205392 A249189 A168200 * A305035 A010654 A244335

Adjacent sequences:  A112884 A112885 A112886 * A112888 A112889 A112890

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Dec 31 2005

EXTENSIONS

Definition corrected by Juri-Stepan Gerasimov, May 17 2010

STATUS

approved

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Last modified September 15 04:28 EDT 2019. Contains 327062 sequences. (Running on oeis4.)