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A067563
Product of n-th prime number and n-th composite number.
5
8, 18, 40, 63, 110, 156, 238, 285, 368, 522, 620, 777, 902, 1032, 1175, 1378, 1593, 1708, 2010, 2272, 2409, 2686, 2905, 3204, 3686, 3939, 4120, 4494, 4796, 5085, 5842, 6288, 6713, 6950, 7599, 7852, 8478, 8965, 9352, 9861, 10382, 10860, 11842, 12159
OFFSET
1,1
LINKS
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