OFFSET
1,1
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = prime(n) * composite(n).
EXAMPLE
E.g. a(4)=63 because the fourth prime is 7 and the fourth composite is 9.
MATHEMATICA
Module[{nn=50, prs, comps, len}, prs=Prime[Range[nn]]; comps=Complement[ Range[ 4, 3nn], prs]; len=Min[nn, Length[comps]]; Times@@@Thread[ {Take[ prs, len], Take[comps, len]}]](* Harvey P. Dale, Sep 02 2015 *)
PROG
(Haskell)
a067563 n = a000040 n * a002808 n -- Reinhard Zumkeller, Apr 30 2014
(Python)
from sympy import prime, composite
def A067563(n):
return prime(n)*composite(n) # Chai Wah Wu, Dec 27 2018
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Rick L. Shepherd, Jan 29 2002
STATUS
approved