id:A069904 - OEIS Search Results

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Number of prime factors of n-th triangular number (with multiplicity).

+0
4

0, 1, 2, 2, 2, 2, 3, 4, 3, 2, 3, 3, 2, 3, 5, 4, 3, 3, 3, 4, 3, 2, 4, 5, 3, 4, 5, 3, 3, 3, 5, 6, 3, 3, 5, 4, 2, 3, 5, 4, 3, 3, 3, 5, 4, 2, 5, 6, 4, 4, 4, 3, 4, 5, 5, 5, 3, 2, 4, 4, 2, 4, 8, 7, 4, 3, 3, 4, 4, 3, 5, 5, 2, 4, 5, 4, 4, 3, 5, 8, 5, 2, 4, 5, 3, 3, 5, 4, 4, 5 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`a(n) = A001222(A000217(n)).`
	EXAMPLE	`A000217(8) = 8(8+1)/2 = 36 = 2233, therefore a(8) = 4.`
	MAPLE	`with(numtheory):with(combinat):a:=proc(n) if n=0 then 0 else bigomega(numbcomp(n+2, n)) fi end: seq(a(n), n=1..90); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 11 2008`
	MATHEMATICA	`Array[Plus@@Last/@FactorInteger[ #*(#+1)/2]&, 33] [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Feb 28 2010]`
	CROSSREFS	`Cf. A069901, A069902, A069903.` `Sequence in context: A005858 A082602 A127444 this_sequence A164978 A119789 A025424` `Adjacent sequences: A069901 A069902 A069903 this_sequence A069905 A069906 A069907`
	KEYWORD	`nonn,new`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 10, 2002`

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Last modified March 20 09:10 EDT 2010. Contains 173642 sequences.

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