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 A100930 #8 Feb 16 2025 08:32:55
%S A100930 22,115,517,6847,31951,128701,516601,1037851,2070001,4156501,4254937,
%T A100930 6045451,7945351,8425957,8777887,9137017,13124317,14278951,14460907,
%U A100930 14920837,24194101,29146501,31795501,47592751,48758797,50108701
%N A100930 Semiprimes of the form (2*p+1)*(p-1)/2, p prime.
%C A100930 a(n) = (2*A059455(n)^2 - A059455(n) - 1) / 2.
%H A100930 Harvey P. Dale, <a href="/A100930/b100930.txt">Table of n, a(n) for n = 1..1000</a>
%H A100930 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Semiprime.html">Semiprime</a>
%H A100930 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SophieGermainPrime.html">Sophie Germain Prime</a>
%t A100930 Select[Table[((2p+1)(p-1))/2,{p,Prime[Range[2000]]}],PrimeOmega[#]==2&] (* _Harvey P. Dale_, Apr 13 2020 *)
%Y A100930 Subsequence of A100929.
%Y A100930 Cf. A001358, A005384, A005385.
%K A100930 nonn
%O A100930 1,1
%A A100930 _Reinhard Zumkeller_, Nov 22 2004