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A068957
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Number of prime divisors of n^n-(n-1)^(n-1), counted with multiplicity.
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2
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1, 1, 1, 2, 2, 1, 4, 6, 3, 1, 3, 2, 4, 3, 2, 1, 2, 3, 4, 2, 2, 3, 3, 4, 9, 4, 2, 2, 5, 4, 6, 3, 6, 4, 4, 2, 6, 7, 6, 4, 3, 4, 8, 6, 2, 7, 4, 7, 12, 6, 4
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,4
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FORMULA
| a(n)=A001222(A007781(n)).
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EXAMPLE
| A007781(14) = 10809131718965763 = 3 * 61^2 * 968299894201, therefore a(14) = 4.
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MATHEMATICA
| Table[ Apply[ Plus, Transpose[ FactorInteger[n^n - (n - 1)^(n - 1)]] [[ -1]]], {n, 2, 52}]
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CROSSREFS
| Cf. A068956.
Sequence in context: A048942 A121484 A080928 * A119468 A175136 A091869
Adjacent sequences: A068954 A068955 A068956 * A068958 A068959 A068960
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KEYWORD
| nonn
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 11 2002
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EXTENSIONS
| Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 15 2002
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