

A160857


n = Product[mPr for all r < m] , mPr = m!/(mr)! , where m,r are both prime numbers.


0



1, 6, 1200, 22226400, 10041430291200000, 1113268229944758412288983040, 591370140954797306733044203963173317440962560, 21844691101536232598885758159278507307951395880466928082689720320
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OFFSET

2,2


LINKS

Table of n, a(n) for n=2..9.


EXAMPLE

Primes = [2,3,5,7,...] Examples: a(1) = 1 (define); a(2) = 3P2 = 6 as 3 is 2nd prime and only prime less than 3 is 2; a(3) = 5P3 . 5P2 = 1200 as 5 is 3rd prime and primes less than 5 are {2,3}; a(4) = 7P5 . 7P3 . 7P2 = 22226400 ; and so on...


PROG

(PARI) a(n) = prod(i=1, n1, prime(n)!/(prime(n)prime(i))!); \\ Michel Marcus, Aug 11 2013


CROSSREFS

Cf. A000040.
Sequence in context: A185537 A113159 A159717 * A160005 A172923 A131675
Adjacent sequences: A160854 A160855 A160856 * A160858 A160859 A160860


KEYWORD

nonn


AUTHOR

Pratik Deoghare (psdeoghare(AT)gmail.com), May 28 2009


STATUS

approved



