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 A247175 #21 Sep 08 2022 08:46:09
%S A247175 0,1,2,7,23,47,98,208,268,278,352,422,712,803,833,887,1022,1048,1052,
%T A247175 1057,1297,1372,1517,1603,1657,1717,1748,1888,1988,2102,2207,2233,
%U A247175 2357,2548,2567,2753,2828,2893,2938,3017,3362,3367,3572,3817,3908,4247,4268,4312,4403,4408,4412,4478
%N A247175 Numbers n such that 2*(n^2 + 2) - 1 and 2*(n^2 + 2) + 1 are both prime.
%C A247175 Numbers n such that 2*n^2 + 3 and 2*n^2 + 5 are both prime.
%H A247175 Harvey P. Dale, <a href="/A247175/b247175.txt">Table of n, a(n) for n = 1..1000</a>
%e A247175 2 is in this sequence because 2*2^2 + 3 = 11 and 2*2^2 + 5 = 13 are both prime.
%t A247175 a247175[n_Integer] := Select[Range[n], And[PrimeQ[2*(#^2 + 2) - 1], PrimeQ[2*(#^2 + 2) + 1]] &]; a247175[4500] (* _Michael De Vlieger_, Nov 30 2014 *)
%t A247175 Select[Range[0,4500],AllTrue[2#^2+{3,5},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Feb 09 2019 *)
%o A247175 (Magma) [ n: n in [0..4500] | IsPrime(2*(n^2+2)-1) and IsPrime(2*(n^2+2)+1) ];
%Y A247175 Cf. A246079, A246699, A247197.
%K A247175 nonn
%O A247175 1,3
%A A247175 _Juri-Stepan Gerasimov_, Nov 30 2014