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 A064904 #23 Oct 08 2020 19:36:07
%S A064904 91,187,247,287,391,581,667,671,679,913,923,973,1147,1169,1261,1267,
%T A064904 1397,1561,1591,1639,1757,1919,1927,1937,2051,2123,2149,2443,2491,
%U A064904 2641,2933,2951,3031,3091,3127,3227,3281,3521,3817,3841,3859,4087,4109,4207
%N A064904 Semiprimes p1*p2 such that p2 mod p1 = 6, with p2 > p1.
%H A064904 John Cerkan, <a href="/A064904/b064904.txt">Table of n, a(n) for n = 1..10000</a>
%t A064904 Module[{pp=200},Select[Union[Times@@@Select[Subsets[Prime[Range[pp]],{2}],Mod[#[[2]],#[[1]]]==6&]],#<=7Prime[pp]&]](* _Harvey P. Dale_, Oct 08 2020 *)
%o A064904 (Python)
%o A064904 from sympy import factorint
%o A064904 def is_A064904(n):
%o A064904 f = factorint(n)
%o A064904 return (sum([f[i] for i in f]) == 2) and (max(f) % min(f) == 6) # _John Cerkan_, Apr 14 2018
%o A064904 (PARI) isok(n) = my(f = factor(n)); (#f~ == 2) && (vecmax(f[,2]) < 2) && ((f[2,1] % f[1,1]) == 6); \\ _Michel Marcus_, Apr 16 2018
%Y A064904 Cf. A001358 (p2 mod p1 = 0), A064899-A064911.
%K A064904 nonn
%O A064904 1,1
%A A064904 _Patrick De Geest_, Oct 13 2001
%E A064904 Offset changed by _John Cerkan_, Apr 12 2018