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A245908
The number of distinct prime factors of prime(n)^2-1.
1
1, 1, 2, 2, 3, 3, 2, 3, 3, 4, 3, 3, 4, 4, 3, 3, 4, 4, 4, 4, 3, 4, 4, 4, 3, 4, 4, 3, 4, 4, 3, 5, 4, 5, 4, 4, 4, 3, 4, 4, 4, 5, 4, 3, 4, 4, 5, 4, 4, 5, 4, 5, 4, 4, 3, 4, 4, 4, 4, 5, 4, 4, 5, 5, 4, 4, 5, 4, 4, 5, 4, 4, 4, 5, 5, 3, 5, 4, 4, 5
OFFSET
1,3
LINKS
FORMULA
a(n) = A082863(prime(n)).
a(n) = A008334(n) + A008335(n) - 1, if n>1.
MAPLE
A245908 := proc(n)
A082863(ithprime(n)) ;
end proc:
MATHEMATICA
Table[PrimeNu[Prime[n]^2 - 1], {n, 100}] (* Wesley Ivan Hurt, Aug 05 2014 *)
PROG
(PARI) vector(100, n, omega(prime(n)^2-1)) \\ Derek Orr, Aug 05 2014
(Magma) [#PrimeDivisors(NthPrime(n)^2 -1): n in [1..100]]; // Vincenzo Librandi, Apr 27 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
R. J. Mathar, Aug 05 2014
STATUS
approved