OFFSET
1,5
LINKS
Max Alekseyev, Table of n, a(n) for n = 1..197 (first 137 terms from Herman Jamke)
Herman Jamke, The first 137 terms in detail
EXAMPLE
a(5)=2 because M(p_5)=M(11)=2047 has 2 (not necessarily distinct) prime factors.
MAPLE
seq(nops(ifactor(2^ithprime(n)-1)), n=1..32); # Emeric Deutsch, Dec 23 2004
MATHEMATICA
Do[m = 2^Prime[n] - 1; Print[Plus @@ Last /@ FactorInteger[m]], {n, 1, 50}] (* Ryan Propper, Jul 31 2005 *)
PROG
(PARI) for(n=1, 137, print1(bigomega(2^prime(n)-1)", ")) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), Apr 28 2007
CROSSREFS
KEYWORD
nonn
AUTHOR
Jeppe Stig Nielsen, Nov 25 2003
EXTENSIONS
14 more terms from Emeric Deutsch, Dec 23 2004
More terms from Ryan Propper, Jul 31 2005
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Apr 28 2007
STATUS
approved