A033477 Products p^3 or p^2*q, where {p,q} are consecutive primes.

8, 12, 18, 27, 45, 75, 125, 175, 245, 343, 539, 847, 1331, 1573, 1859, 2197, 2873, 3757, 4913, 5491, 6137, 6859, 8303, 10051, 12167, 15341, 19343, 24389, 26071, 27869, 29791, 35557, 42439, 50653, 56129, 62197, 68921, 72283, 75809, 79507, 86903, 94987, 103823

Offset

0,1

Links

Robert Israel, Table of n, a(n) for n = 0..10000

Formula

From Robert Israel, Jun 26 2020: (Start)

a(3k) = A030078(k+1).

a(3k+1) = A251720(k+1).

a(3k+2) = a(3k+1)^2/a(3k). (End)

Maple

R:= NULL: p:= 2:
for n from 1 to 30 do
  q:= nextprime(p);
  R:= R, p^3, p^2*q, p*q^2;
  p:= q;
od:
R; # Robert Israel, Jun 26 2020

Mathematica

nn=50; With[{prs=Prime[Range[nn]]}, Take[Union[Flatten[{prs^3, {#[[1]]^2 #[[2]], #[[2]]^2 #[[1]]}&/@Partition[prs, 2, 1]}]], nn]] (* Harvey P. Dale, Dec 28 2013 *)

Crossrefs

Cf. A030078, A251720.

Sequence in context: A120137 A274951 A364776 * A105936 A168670 A291758

Adjacent sequences: A033474 A033475 A033476 * A033478 A033479 A033480

Keyword

nonn

Author

Jeff Burch

Extensions

Corrected and extended by Harvey P. Dale, Dec 28 2013

Status

approved