cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A344872 Semiprimes of the form 3m+2.

This page as a plain text file.
%I A344872 #8 Jun 02 2021 22:09:47
%S A344872 14,26,35,38,62,65,74,77,86,95,119,122,134,143,146,155,158,161,185,
%T A344872 194,203,206,209,215,218,221,254,278,287,299,302,305,314,323,326,329,
%U A344872 335,341,362,365,371,377,386,395,398,407,413,422,437,446,458,473,482,485,497
%N A344872 Semiprimes of the form 3m+2.
%C A344872 There are no square terms, as squares are congruent to 0 or 1 modulo 3.
%C A344872 Products of a prime of the form 3m+1 and a prime of the form 3m+2 (the former necessarily being of the form 6m+1).
%e A344872 14 = 2 * 7 has 2 prime factors (counting repetitions) so is a semiprime, and 14 = 3*4 + 2, so has the form 3m+2. So 14 is in the sequence.
%t A344872 Select[Range[2,500,3],PrimeOmega@#==2&] (* _Giorgos Kalogeropoulos_, Jun 02 2021 *)
%o A344872 (PARI) isok(m) = bigomega(m) == 2 && m % 3 == 2;
%Y A344872 Intersection of A001358 and A016789.
%Y A344872 Disjoint union of A108172 and A112772.
%Y A344872 Complement within A001358 of A001748, A112771 and A112774.
%Y A344872 Subsequence of A344703.
%K A344872 nonn,easy
%O A344872 1,1
%A A344872 _Peter Munn_, May 31 2021