A071215 - OEIS

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A071215

Number of distinct prime factors of sum of 2 successive prime.

1, 1, 2, 2, 2, 3, 2, 3, 2, 3, 2, 3, 3, 3, 2, 2, 3, 1, 3, 2, 2, 2, 2, 3, 3, 3, 4, 2, 3, 3, 3, 2, 3, 2, 3, 3, 2, 4, 3, 2, 3, 3, 2, 4, 3, 3, 3, 3, 3, 4, 2, 3, 3, 2, 3, 3, 3, 2, 3, 3, 2, 3, 3, 3, 4, 2, 2, 3, 3, 3, 2, 3, 3, 2, 3, 2, 3, 4, 3, 3, 4, 3, 2, 2, 3, 2, 3, 3, 4, 4, 3, 4, 3, 4, 3, 3, 3, 3, 3, 2, 3, 3, 2, 4, 3 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,3`
	FORMULA	`a(n)=A001221[A001043(n)]`
	MATHEMATICA	`lf[x_] := Length[FactorInteger[x]] Table[lf[Prime[w+1]+Prime[w]], {w, 1, 128}]`
	PROG	`(PARI) A071215(n)=omega(prime(n)+prime(n+1)) - M. F. Hasler (maximilian.hasler(AT)gmail.com), Jul 23 2007`
	CROSSREFS	`Cf. A001221, A001043, A071216.` `Sequence in context: A093429 A089842 A091322 * A164024 A145193 A175872` `Adjacent sequences: A071212 A071213 A071214 * A071216 A071217 A071218`
	KEYWORD	`easy,nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu), May 17 2002`

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Last modified February 15 23:53 EST 2012. Contains 205860 sequences.