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 A290434 #13 Sep 25 2019 13:44:13
%S A290434 4,9,21,25,35,39,55,57,65,77,85,111,115,121,129,155,161,185,187,201,
%T A290434 203,205,209,221,235,237,265,291,299,305,309,319,323,327,335,341,365,
%U A290434 371,377,381,391,413,415,437,451,485,489,493,497,505,515,517,529,535,579
%N A290434 Semiprimes of the form pq such that p+q+1 is prime.
%C A290434 4 is the only even term.
%H A290434 Chai Wah Wu, <a href="/A290434/b290434.txt">Table of n, a(n) for n = 1..10000</a>
%e A290434 377 = 13*29 and 13+29+1 is prime, so 377 is a term.
%t A290434 With[{nn = 55}, Take[#, nn] &@ Union@ Flatten@ Table[Function[p, Map[Times @@ # &@ # &, #] &@ Select[Map[{p, #} &, Prime@ Range[PrimePi@ p]], PrimeQ[Total@ # + 1] &]]@ Prime@ n, {n, nn + 4}]] (* _Michael De Vlieger_, Aug 01 2017 *)
%t A290434 Select[Range[600],PrimeOmega[#]==2&&PrimeQ[Total[Times@@@ FactorInteger[ #]]+1]&] (* _Harvey P. Dale_, Sep 25 2019 *)
%o A290434 (Python)
%o A290434 from sympy import factorint, isprime
%o A290434 A290434_list = [n for n in range(2,10**5) if sum(factorint(n).values()) == 2 and isprime(1+sum(factorint(n).keys())*(3-len(factorint(n))))]
%o A290434 (PARI) isok(n) = {if (bigomega(n) == 2, f = factor(n); if (#f~ == 1, isprime(2*f[1,1]+1), isprime(vecsum(f[,1]+1))););} \\ _Michel Marcus_, Aug 02 2017
%Y A290434 Cf. A001358.
%K A290434 nonn
%O A290434 1,1
%A A290434 _Chai Wah Wu_, Aug 01 2017