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 A109288 #13 Aug 08 2025 03:24:47
%S A109288 15,22,34,35,39,58,86,87,94,95,119,123,134,142,143,146,159,178,202,
%T A109288 203,206,214,215,218,219,254,299,302,303,327,335,382,394,395,446,447,
%U A109288 454,482,502,515,527,538,543,554,566,623,634,635,695,698,699,707,718,746
%N A109288 Semiprimes equal to p*q + 1, where p and q are distinct primes.
%H A109288 Amiram Eldar, <a href="/A109288/b109288.txt">Table of n, a(n) for n = 1..10000</a>
%F A109288 a(n) = A263990(n) + 1. - _Amiram Eldar_, Aug 08 2025
%t A109288 With[{nn=60},Take[Select[Union[Times@@#+1&/@Subsets[Prime[Range[2nn]],{2}]],PrimeOmega[#]==2&],nn]] (* _Harvey P. Dale_, Apr 28 2018 *)
%t A109288 Select[Range[1000], !IntegerQ[Sqrt[#-1]] && PrimeOmega[#] == PrimeOmega[#-1] == 2 &] (* _Amiram Eldar_, Aug 08 2025 *)
%o A109288 (PARI) for(i=1,1000,if(bigomega(i)==2&&bigomega(i+1)==2&&issquare(i)==0,print1(i+1,","))) \\ Lambert Klasen (lambert.klasen(AT)gmx.net), Aug 21 2005
%Y A109288 Cf. A109287, A109289, A109290, A263990.
%K A109288 nonn
%O A109288 1,1
%A A109288 _Giovanni Teofilatto_, Aug 20 2005
%E A109288 More terms from Lambert Klasen (lambert.klasen(AT)gmx.net), Aug 21 2005