A067563 Product of n-th prime number and n-th composite number.

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

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

Cf. A000040, A002808, A064799.

Cf. A127118, A038529.

Sequence in context: A082227 A134062 A251251 * A211477 A123134 A096283

Adjacent sequences: A067560 A067561 A067562 * A067564 A067565 A067566

Keyword

easy,nonn

Author

Rick L. Shepherd, Jan 29 2002

Status

approved