

A079078


a(0) = 1, a(1) = 2; for n>1, a(n) = p(n)*a(n2) where p(n) is the nth prime.


7



1, 2, 3, 10, 21, 110, 273, 1870, 5187, 43010, 150423, 1333310, 5565651, 54665710, 239322993, 2569288370, 12684118629, 151588013830, 773731236369, 10156396926610, 54934917782199, 741416975642530, 4339858504793721
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OFFSET

0,2


COMMENTS

Might be called the double primorial numbers and denoted by n##, by analogy with the double factorial numbers.


LINKS

Table of n, a(n) for n=0..22.


EXAMPLE

a(5)=110 because 2*5*11=110, the product of the first, third and fifth primes


PROG

(PARI) A079078(n)=prod(i=0, (n1)\2, prime(n2*i)) \\  M. F. Hasler, May 04 2008


CROSSREFS

Cf. A006882, A002110.
Sequence in context: A161522 A120484 A113202 * A285794 A148056 A148057
Adjacent sequences: A079075 A079076 A079077 * A079079 A079080 A079081


KEYWORD

nonn


AUTHOR

Michael Joseph Halm, Feb 02 2003


EXTENSIONS

Last term corrected by Jonathan Vos Post, Feb 09 2006
Edited and corrected by M. F. Hasler, May 06 2008


STATUS

approved



