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 A105106 #21 Jul 08 2021 03:10:28 %S A105106 0,5,6,8,12,15,20,21,29,42,44,50,53,54,56,60,65,72,74,77,78,81,83,89, %T A105106 95,98,102,107,116,117,119,125,131,135,138,141,149,170,174,177,182, %U A105106 194,197,201,204,210,221,224,230,240,242,243,252,258,261,263,264,282,285,291 %N A105106 Numbers k such that the string k101 is prime. %C A105106 Also numbers k such that 1000*k + 101 is prime. - _Stefan Steinerberger_, Feb 21 2006 %H A105106 Daniel Starodubtsev, <a href="/A105106/b105106.txt">Table of n, a(n) for n = 1..10000</a> %e A105106 If k=0, then k101 = 0101 (prime). %e A105106 If k=42, then k101 = 42101 (prime). %p A105106 q:= n-> isprime(parse(cat(n, 101))): %p A105106 select(q, [$0..300])[]; # _Alois P. Heinz_, Jan 23 2020 %t A105106 For[n = 0, n < 300, n++, If[PrimeQ[1000*n + 101], Print[n]]] (* _Stefan Steinerberger_, Feb 21 2006 *) %o A105106 (PARI) is(n)=isprime(1000*n+101) \\ _Charles R Greathouse IV_, May 22 2017 %K A105106 base,nonn %O A105106 1,2 %A A105106 _Parthasarathy Nambi_, Apr 07 2005 %E A105106 More terms from _Stefan Steinerberger_, Feb 21 2006 %E A105106 Missing a(11)=44 inserted by _Daniel Starodubtsev_, Jan 23 2020