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 A023206 #31 Sep 08 2022 08:44:47 %S A023206 2,3,5,11,17,23,41,47,53,71,83,113,131,137,173,191,197,227,251,257, %T A023206 281,293,317,347,383,401,461,467,503,521,587,593,641,647,677,683,701, %U A023206 743,773,797,857,863,941,947,953,971,983,1031,1061,1103,1151,1163,1187,1193,1217 %N A023206 Numbers m such that m and 2*m + 7 both prime. %C A023206 Subsequence of A105760. Except for the first two terms, all terms are congruent to 5 mod 6. - _John Cerkan_, Sep 07 2016 %H A023206 Vincenzo Librandi, <a href="/A023206/b023206.txt">Table of n, a(n) for n = 1..1000</a> %p A023206 A023206:=n->`if`(isprime(n) and isprime(2*n+7), n, NULL): seq(A023206(n), n=1..3*1000); # _Wesley Ivan Hurt_, Sep 07 2016 %t A023206 Select[Prime@Range@250,PrimeQ[2#+7]&] (* _Vladimir Joseph Stephan Orlovsky_, Apr 25 2011 *) %o A023206 (Magma) [n: n in [0..1000] | IsPrime(n) and IsPrime(2*n+7)]; // _Vincenzo Librandi_, Nov 20 2010 %o A023206 (PARI) is(n)=isprime(2*n+7) && isprime(n) \\ _Charles R Greathouse IV_, Sep 07 2016 %Y A023206 Cf. A005384, A023204, A023205. %K A023206 nonn,easy %O A023206 1,1 %A A023206 _David W. Wilson_