

A259026


Numbers n such that n*23^n1 is semiprime.


0



1, 2, 6, 8, 18, 21, 24, 26, 28, 30, 33, 230
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OFFSET

1,2


COMMENTS

After 290, which may or may not be in the sequence, 420 and 450 are definitely in the sequence.


LINKS

Table of n, a(n) for n=1..12.
K. O'Bryant, Sets of Natural Numbers with Proscribed Subsets, J. Int. Seq. 18 (2015) # 15.7.7


MATHEMATICA

Select[Range[200], PrimeOmega[# 23^#  1]==2&]


PROG

(MAGMA) IsSemiprime:=func<i  &+[d[2]: d in Factorization(i)] eq 2>; [n: n in [2..200]  IsSemiprime(s) where s is n*23^n1];
(PARI) isok(n)=bigomega(n*23^n1)==2 \\ Anders HellstrÃ¶m, Aug 20 2015


CROSSREFS

Similar sequences listed in A242273.
Sequence in context: A053355 A233572 A005823 * A178758 A024431 A152598
Adjacent sequences: A259023 A259024 A259025 * A259027 A259028 A259029


KEYWORD

nonn,more


AUTHOR

Luke March, Aug 06 2015


STATUS

approved



