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A088863
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Number of prime factors of n-th Mersenne number M(p_n).
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6
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1, 1, 1, 1, 2, 1, 1, 1, 2, 3, 1, 2, 2, 3, 3, 3, 2, 1, 2, 3, 3, 3, 2, 1, 2, 2, 2, 1, 2, 5, 1, 2, 2, 2, 2, 5, 4, 5, 2, 4, 3, 4, 5, 3, 2, 2, 3, 6, 2, 4, 4, 6, 2, 5, 3, 4, 2, 2, 3, 2, 3, 2, 5, 3, 4, 4, 3, 5, 2, 3, 3, 6, 5, 2, 2, 5, 3, 9, 4, 3, 5, 2, 8, 4, 4, 3, 5, 2, 4, 6, 3, 4, 2, 7, 3, 4, 4, 1, 2, 5, 4, 5, 3, 5, 4
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OFFSET
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1,5
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COMMENTS
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LINKS
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EXAMPLE
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a(5)=2 because M(p_5)=M(11)=2047 has 2 (not necessarily distinct) prime factors.
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MAPLE
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seq(nops(ifactor(2^ithprime(n)-1)), n=1..32); # Emeric Deutsch, Dec 23 2004
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MATHEMATICA
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Do[m = 2^Prime[n] - 1; Print[Plus @@ Last /@ FactorInteger[m]], {n, 1, 50}] (* Ryan Propper, Jul 31 2005 *)
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PROG
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(PARI) for(n=1, 137, print1(bigomega(2^prime(n)-1)", ")) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), Apr 28 2007
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Apr 28 2007
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STATUS
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approved
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