A122123 Product of the first n 5-almost primes (A014614).

32, 1536, 110592, 8847360, 955514880, 107017666560, 12842119987200, 2080423437926400, 349511137571635200, 61513960212607795200, 11072512838269403136000, 2214502567653880627200000, 460616534072007170457600000, 111929817779497742421196800000

Offset

1,1

Comments

5-almost prime analog of primorial (A002110). The semiprime analog of primorial is A112141. Equivalent for product of what A086047 is for sum. Bigomega(a(n)) = the number of not necessarily distinct prime factors of a(n) = A001222(a(n)) = A008587(n) = 5*n.

Links

Table of n, a(n) for n=1..14.

Formula

a(n) = Prod[i=1..n] A014614(i).

Example

a(10) = 32 * 48 * 72 * 80 * 108 * 112 * 120 * 162 * 168 * 176 = 2^33 * 3^12 * 5^2 * 7^2 * 11 which has 50 prime factors with multiplicity.

Mathematica

Rest[FoldList[Times, 1, Select[Range[200], PrimeOmega[#]==5&]]] (* Harvey P. Dale, Feb 07 2012 *)

Crossrefs

Cf. A001222, A002110, A008585, A014613, A008587, A086046, A086047, A112141, A114426.

Sequence in context: A301448 A220577 A200258 * A357571 A013994 A281953

Adjacent sequences: A122120 A122121 A122122 * A122124 A122125 A122126

Keyword

easy,nonn

Author

Jonathan Vos Post, Oct 19 2006

Extensions

More terms from Harvey P. Dale, Feb 07 2012

Status

approved