id:A112325 - OEIS Search Results

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Number of even semiprimes <= semiprime(n).

+0
2

1, 2, 2, 3, 4, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 9, 9, 9, 10, 11, 11, 11, 12, 12, 13, 13, 14, 14, 14, 14, 15, 15, 16, 16, 16, 17, 17, 17, 18, 18, 18, 18, 19, 19, 20, 20, 20, 21, 21, 22, 22, 22, 23, 23, 23, 24, 24, 24, 24, 25, 25, 26, 26, 26, 27, 27, 27, 28, 28, 28, 29, 29, 29, 30 (list; graph; listen)

	OFFSET	`1,2`
	MATHEMATICA	`spQ[n_] := Plus @@ Last /@ FactorInteger@n == 2; sp = Select[Range@300, spQ[ # ] &]; f[n_] := Length[Select[Take[sp, n], EvenQ[ # ] &]]; Array[f, 76] (* Robert G. Wilson v *)`
	CROSSREFS	`Sequence in context: A089576 A076642 A135304 this_sequence A029111 A092038 A046699` `Adjacent sequences: A112322 A112323 A112324 this_sequence A112326 A112327 A112328`
	KEYWORD	`nonn`
	AUTHOR	`Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), Dec 01 2005`
	EXTENSIONS	`More terms from Stefan Steinerberger (hansibal(AT)hotmail.com) and Robert G. Wilson v (rgwv(at)rgwv.com), Dec 02 2005`

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Last modified August 8 13:43 EDT 2008. Contains 142651 sequences.

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