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A125072
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a(n) = number of exponents in the prime-factorization of n which are triangular numbers.
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1
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0, 1, 1, 0, 1, 2, 1, 1, 0, 2, 1, 1, 1, 2, 2, 0, 1, 1, 1, 1, 2, 2, 1, 2, 0, 2, 1, 1, 1, 3, 1, 0, 2, 2, 2, 0, 1, 2, 2, 2, 1, 3, 1, 1, 1, 2, 1, 1, 0, 1, 2, 1, 1, 2, 2, 2, 2, 2, 1, 2, 1, 2, 1, 1, 2, 3, 1, 1, 2, 3, 1, 1, 1, 2, 1, 1, 2, 3, 1, 1, 0, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 1, 2, 2, 2, 1, 1, 1, 1, 0, 1, 3, 1, 2, 3
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,6
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EXAMPLE
| The prime-factorzation of 360 is 2^3 *3^2 *5^1. There are two exponents in this factorization which are triangular numbers, 1 and 3. So a(360) = 2.
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MATHEMATICA
| f[n_] := Length @ Select[Last /@ FactorInteger[n], IntegerQ[Sqrt[8# + 1]] &]; Table[f[n], {n, 110}] (*Chandler*)
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CROSSREFS
| Cf. A125073.
Sequence in context: A078134 A083661 A029369 * A162642 A139146 A144032
Adjacent sequences: A125069 A125070 A125071 * A125073 A125074 A125075
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KEYWORD
| nonn
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AUTHOR
| Leroy Quet, Nov 18 2006
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EXTENSIONS
| Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 19 2006
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