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 A085722 #28 Apr 14 2024 23:25:22
%S A085722 3,5,8,9,11,12,15,19,22,25,28,29,30,34,35,39,42,44,45,46,48,49,50,51,
%T A085722 52,58,59,60,61,62,64,65,69,71,76,78,79,80,85,86,88,92,95,96,100,101,
%U A085722 102,104,106,108,114,121,131,136,139,140,141,144,145,152,154,158,159,164
%N A085722 Numbers k such that k^2 + 1 is a semiprime.
%C A085722 Corresponding semiprimes k^2+1 are in A144255.
%C A085722 Solutions to the equation: A000005(1+k^2) = 4. - _Enrique Pérez Herrero_, May 03 2012
%H A085722 T. D. Noe, <a href="/A085722/b085722.txt">Table of n, a(n) for n = 1..1000</a>
%F A085722 A085722 = A193432^-1({2}). - _M. F. Hasler_, Mar 11 2012
%t A085722 lst={}; Do[If[Plus@@Last/@FactorInteger[n^2+1]==2, AppendTo[lst,n]], {n,0,200}]; lst (* _Vladimir Joseph Stephan Orlovsky_, Mar 24 2009 *)
%t A085722 Select[Range[200],PrimeOmega[#^2+1]==2&] (* _Harvey P. Dale_, Feb 28 2013 *)
%o A085722 (PARI) select(vector(50,n,n),n->bigomega(n^2+1)==2)
%o A085722 \\ _Zak Seidov_, Feb 25 2011
%Y A085722 Cf. A014442, A089120, A144255, A193432.
%K A085722 easy,nonn
%O A085722 1,1
%A A085722 _Jason Earls_, Jul 20 2003