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A068956 Number of distinct prime factors of n^n-(n-1)^(n-1). 4
1, 1, 1, 2, 2, 1, 3, 6, 3, 1, 3, 2, 3, 3, 2, 1, 2, 3, 3, 2, 2, 3, 3, 4, 7, 4, 2, 2, 5, 4, 5, 3, 6, 4, 4, 2, 4, 7, 6, 4, 3, 4, 7, 6, 2, 7, 4, 7, 10, 6, 4 (list; graph; refs; listen; history; internal format)
OFFSET

2,4

FORMULA

a(n)=A001221(A007781(n)).

EXAMPLE

A007781(14) = 10809131718965763 = 3 * 61^2 * 968299894201, therefore a(14) = 3.

MATHEMATICA

Table[ Length[ FactorInteger[n^n - (n - 1)^(n - 1)]], {n, 2, 52}]

CROSSREFS

Cf. A068957.

Sequence in context: A125231 A117919 A160014 * A124842 A134399 A094436

Adjacent sequences:  A068953 A068954 A068955 * A068957 A068958 A068959

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 11 2002

EXTENSIONS

Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 15 2002

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Last modified February 17 21:13 EST 2012. Contains 206085 sequences.