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 A206328 #12 Jan 16 2023 16:31:48 %S A206328 5,17,197,577,2917,15377,41617,147457,215297,401957,414737,509797, %T A206328 1196837,1308737,1378277,1547537,1623077,1726597,1887877,2446097, %U A206328 2604997,2802277,2835857,3857297,4218917,4343057,4384837,5779217,6022117,6421157,7096897,8031557 %N A206328 Primes of the form n^2+1 such that (n+2)^2+1 is also prime. %C A206328 Primes corresponding to A096012 and subset of A002496. %C A206328 For n > 1, a(n) ==7 (mod 10) because n ==4 (mod 10). %C A206328 Conjecture: this sequence is infinite. %H A206328 Harvey P. Dale, <a href="/A206328/b206328.txt">Table of n, a(n) for n = 1..1000</a> %e A206328 For n = 4, n^2 + 1 = 17 is prime and (n+2)^2 + 1 = 37 is also prime => 17 is in the sequence. %p A206328 for n from 1 to 4000 do: x:=n^2+1:y:=(n+2)^2+1:if type(x,prime)=true and type(y,prime)=true then printf(`%d, `,x): else fi:od: %t A206328 Select[Partition[Range[3000]^2+1,3,1],AllTrue[{#[[1]],#[[3]]},PrimeQ]&][[All,1]] (* _Harvey P. Dale_, Jan 16 2023 *) %Y A206328 Cf. A096012, A002496. %K A206328 nonn,easy %O A206328 1,1 %A A206328 _Michel Lagneau_, Feb 06 2012