A111687 Comprimorial(n): the product of the first n primes and the first n composite numbers.

8, 144, 5760, 362880, 39916800, 6227020800, 1482030950400, 422378820864000, 155435406077952000, 81137281972690944000, 50305114823068385280000, 39087074217524135362560000, 35256540944206770097029120000

Offset: 1

Author

Amarnath Murthy, Aug 17 2005

Keywords

• nonn

Examples

			a(1) = 2*4 = 8, a(2) = (2*3)*(4*6)=144.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..215

Crossrefs

Cf. A002110 (primorials), A036691 (compositorials).

Programs

Mathematica

Module[{nn=50,prs,coms,len},prs=Select[Range[nn],PrimeQ];coms=Complement[ Range[4,nn],prs];len=Min[Length[prs],Length[coms]];Rest[FoldList[ Times, 1, Times@@@Thread[{Take[prs,len],Take[coms,len]}]]]] (* Harvey P. Dale, Jan 11 2014 *)

Formula

a(n) = A002110(n)*A036691(n) for n>=1. - Rick L. Shepherd, Aug 20 2005

Extensions

Corrected and extended by Rick L. Shepherd, Aug 20 2005