A337877 Numbers of the form p^2*q where p and q are primes and p <= q.

8, 12, 20, 27, 28, 44, 45, 52, 63, 68, 76, 92, 99, 116, 117, 124, 125, 148, 153, 164, 171, 172, 175, 188, 207, 212, 236, 244, 261, 268, 275, 279, 284, 292, 316, 325, 332, 333, 343, 356, 369, 387, 388, 404, 412, 423, 425, 428, 436, 452, 475, 477, 508, 524, 531, 539, 548, 549, 556, 575, 596, 603

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

a(3) = 20 is a term because 20=2^2*5 with 2 <= 5.

Maple

N:= 3000: # for terms <= N
P:= select(isprime, [2, seq(i, i=3..N/2, 2)]): nP:= nops(P):
R:= NULL:
for i from 1 to nP do
  p2:= P[i]^2;
  for j from i to nP do
    x:= p2*P[j];
    if x > N then break fi;
    R:= R, x
od od:
sort([R]);

Crossrefs

Contained in A337806.

Sequence in context: A232867 A358574 A084488 * A211410 A001749 A175786

Adjacent sequences: A337874 A337875 A337876 * A337878 A337879 A337880

Keyword

nonn

Author

Robert Israel, Sep 27 2020

Status

approved