OFFSET
2,4
EXAMPLE
A007781(13) = 10809131718965763 = 3 * 61^2 * 968299894201, therefore a(14) = 3.
MATHEMATICA
Table[ Length[ FactorInteger[n^n - (n - 1)^(n - 1)]], {n, 2, 52}] (* Reinhard Zumkeller *)
PrimeNu[#]&/@(#[[2]]-#[[1]]&/@Partition[Table[n^n, {n, 52}], 2, 1] (* Harvey P. Dale, Aug 24 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Mar 11 2002
EXTENSIONS
Edited and extended by Robert G. Wilson v, Mar 15 2002
a(53)-a(54) from Alois P. Heinz, May 12 2017
a(55)-a(86) from Amiram Eldar, Feb 06 2020
STATUS
approved