login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A193295
Number of prime divisors (with multiplicity) of n^2 - 1.
2
1, 3, 2, 4, 2, 5, 3, 5, 3, 5, 2, 5, 3, 6, 3, 7, 2, 6, 3, 5, 3, 6, 3, 6, 5, 5, 4, 6, 2, 8, 3, 7, 4, 6, 3, 6, 3, 6, 3, 7, 2, 6, 4, 5, 4, 7, 3, 8, 4, 6, 3, 7, 3, 8, 4, 6, 3, 6, 2, 6, 4, 8, 5, 9, 3, 6, 3, 6, 3, 8, 2, 7, 4, 5, 5, 6, 3, 8, 5, 7, 5, 6, 3, 6, 4, 6
OFFSET
2,2
MATHEMATICA
Table[PrimeOmega[n^2 - 1], {n, 100}] (* Vladimir Joseph Stephan Orlovsky, Jul 22 2011 *)
PROG
(PARI) a(n)=bigomega(n^2-1) \\ Charles R Greathouse IV, Jul 30 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved