

A063487


Number of distinct prime divisors of 2^(2^n)1 (A051179).


0



0, 1, 2, 3, 4, 5, 7, 9, 11, 13, 16, 20, 25
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OFFSET

0,3


COMMENTS

2^(2^n)1 is the product of the first n Fermat numbers F(0),...,F(n1) (A000215). Hence this sequence is just the summation of A046052, which gives the number of prime factors in each Fermat number.  T. D. Noe, Jan 07 2003


REFERENCES

D. M. Burton, Elementary Number Theory, Allyn and Bacon Inc., Boston MA, 1976, p. 238.


LINKS

Table of n, a(n) for n=0..12.
Eric Weisstein's World of Mathematics, Fermat Number


PROG

(PARI) for(n=0, 22, print(omega(2^(2^n)1)))


CROSSREFS

Cf. A051179, A000215, A046052.
Sequence in context: A158923 A008740 A089651 * A253063 A081998 A284288
Adjacent sequences: A063484 A063485 A063486 * A063488 A063489 A063490


KEYWORD

nonn


AUTHOR

Jason Earls, Jul 28 2001


EXTENSIONS

More terms from T. D. Noe, Jan 07 2003


STATUS

approved



