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A069904
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Number of prime factors of n-th triangular number (with multiplicity).
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3
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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; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| a(n) = A001222(A000217(n)).
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EXAMPLE
| A000217(8) = 8*(8+1)/2 = 36 = 2*2*3*3, therefore a(8) = 4.
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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
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MATHEMATICA
| Array[Plus@@Last/@FactorInteger[ #*(#+1)/2]&, 33] [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Feb 28 2010]
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CROSSREFS
| Cf. A069901, A069902, A069903.
Sequence in context: A005858 A082602 A171931 * A164978 A119789 A025424
Adjacent sequences: A069901 A069902 A069903 * A069905 A069906 A069907
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KEYWORD
| nonn
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 10, 2002
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