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A069461
Number of distinct prime factors of prime(n)^n-1.
4
0, 1, 2, 3, 3, 5, 2, 6, 6, 8, 7, 11, 5, 7, 9, 8, 5, 12, 4, 13, 8, 10, 4, 16, 7, 12, 12, 13, 6, 18, 4, 15, 10, 8, 10, 19, 8, 9, 8, 17, 5, 21, 5, 13, 16, 16, 6, 21, 9, 12, 9, 15, 10, 20, 9, 22, 9, 17, 7, 31, 7, 11, 13, 21, 9, 17, 11, 16, 14, 21, 5, 32, 7, 12, 16
OFFSET
1,3
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..96 (using factordb.com)
FORMULA
a(n) = A001221(A069459(n)).
EXAMPLE
A000040(8)^8-1 = 19^8 - 1 = 16983563040 = 2^5*3^2*5*17*181*3833, therefore a(8) = 6 and A069462(8) = 11.
A000040(9)^9-1 = 23^9-1 = 1801152661462 = 2*7*11*19*79*7792003, therefore a(9) = 6 and A069462(9) = 6.
MATHEMATICA
Table[PrimeNu[Prime[n]^n - 1], {n, 1, 30}] (* Amiram Eldar, Feb 17 2020 *)
PROG
(PARI) for(n=1, 52, print1(omega(prime(n)^n-1)", ")) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Mar 24 2002
EXTENSIONS
More terms from Hugo Pfoertner, May 18 2004
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
a(53)-a(75) using factordb.com from Amiram Eldar, Feb 17 2020
STATUS
approved