id:A125030 - OEIS Search Results

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a(n) = sum of exponents in the prime-factorization of n which are noncomposite.

+0
2

0, 1, 1, 2, 1, 2, 1, 3, 2, 2, 1, 3, 1, 2, 2, 0, 1, 3, 1, 3, 2, 2, 1, 4, 2, 2, 3, 3, 1, 3, 1, 5, 2, 2, 2, 4, 1, 2, 2, 4, 1, 3, 1, 3, 3, 2, 1, 1, 2, 3, 2, 3, 1, 4, 2, 4, 2, 2, 1, 4, 1, 2, 3, 0, 2, 3, 1, 3, 2, 3, 1, 5, 1, 2, 3, 3, 2, 3, 1, 1, 0, 2, 1, 4, 2, 2, 2, 4, 1, 4, 2, 3, 2, 2, 2, 6, 1, 3, 3, 4, 1, 3, 1, 4, 3 (list; graph; listen)

	OFFSET	`1,4`
	LINKS	`Leroy Quet, Home Page (listed in lieu of email address)`
	EXAMPLE	`a(720) = 3, since the prime-factorization of 720 is 2^4 3^2 5^1 and 2 of the exponents in this factorization are non-composites (the exponents 2 and 1, which when added is 3).`
	MATHEMATICA	`f[n_] := Plus @@ Select[Last /@ FactorInteger[n], # == 1 \|\| PrimeQ[ # ] &]; Table[f[n], {n, 110}] (Chandler)`
	CROSSREFS	`Cf. A125029.` `Sequence in context: A147810 A055181 A073811 this_sequence A116479 A122810 A086436` `Adjacent sequences: A125027 A125028 A125029 this_sequence A125031 A125032 A125033`
	KEYWORD	`nonn`
	AUTHOR	`Leroy Quet, Nov 16 2006`
	EXTENSIONS	`Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 19 2006`

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.

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