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.
%I A367576 #12 Nov 24 2023 08:58:56 %S A367576 10,21,26,34,39,55,57,58,74,82,93,106,111,122,129,146,155,178,183,194, %T A367576 201,202,203,205,218,219,226,237,253,274,291,298,301,305,309,314,327, %U A367576 346,355,362,381,386,394,417,453,458,466,471,482,489,497,505,514,538 %N A367576 Semiprimes p*q such that 2*p divides q-1. %C A367576 These terms and their squarefree proper multiples are the squarefree numbers that never appear as terms in A367566. %e A367576 10 is a term: 10 = 2*5, and 2*2 | 5 - 1. %e A367576 33 is not a term: 33 = 3*11, but 2*3 does not divide 11 - 1. %Y A367576 Cf. A156592, A231966, A367566. %Y A367576 Subsequence of A006881. %K A367576 nonn %O A367576 1,1 %A A367576 _Jon E. Schoenfield_, Nov 24 2023