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 A024912 #52 Aug 20 2024 15:32:07 %S A024912 1,3,4,6,7,10,13,15,18,19,21,24,25,27,28,31,33,40,42,43,46,49,52,54, %T A024912 57,60,63,64,66,69,70,75,76,81,82,88,91,94,97,99,102,103,105,106,109, %U A024912 115,117,118,120,123,129,130,132,136,138,145,147,148,151,153,157,160,162 %N A024912 Numbers k such that 10*k + 1 is prime. %H A024912 T. D. Noe, <a href="/A024912/b024912.txt">Table of n, a(n) for n = 1..1000</a> %F A024912 a(n) = (A081759(n)+1)/2. %t A024912 Select[Range[170], PrimeQ[10# + 1] &] (* _Ray Chandler_, Dec 06 2006 *) %o A024912 (Magma) [n: n in [1..1000] |IsPrime(10*n+1)]; // _Vincenzo Librandi_, Nov 19 2010 %o A024912 (PARI) is(n)=isprime(10*n+1) \\ _Charles R Greathouse IV_, Jul 02 2013 %Y A024912 Cf. A030430, A049511, A081759. %K A024912 nonn,easy %O A024912 1,2 %A A024912 _Clark Kimberling_