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A111687 Comprimorial(n): the product of the first n primes and the first n composite numbers. 2
8, 144, 5760, 362880, 39916800, 6227020800, 1482030950400, 422378820864000, 155435406077952000, 81137281972690944000, 50305114823068385280000, 39087074217524135362560000, 35256540944206770097029120000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

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

EXAMPLE

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

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 *)

CROSSREFS

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

Sequence in context: A052764 A024284 A024285 * A231851 A071305 A172150

Adjacent sequences:  A111684 A111685 A111686 * A111688 A111689 A111690

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Aug 17 2005

EXTENSIONS

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

STATUS

approved

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Last modified February 15 22:28 EST 2019. Contains 320138 sequences. (Running on oeis4.)