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 A103408 #14 Sep 08 2022 08:45:16 %S A103408 1,4,7,10,18,24,25,28,31,34,39,42,48,51,63,70,73,76,79,81,85,93,94, %T A103408 100,126,139,148,150,156,157,160,163,168,174,177,184,186,199,202,207, %U A103408 219,232,234,235,237,265,268,277,300,301,307,309,315,316,321,322,328,343,354,358,364,366 %N A103408 Numbers n such that n2101 is prime. %H A103408 Harvey P. Dale, <a href="/A103408/b103408.txt">Table of n, a(n) for n = 1..1000</a> %e A103408 If n=1, then n2101 = 12101 (prime). %e A103408 If n=31, then n2101 = 312101 (prime). %e A103408 If n=63, then n2101 = 632101 (prime). %t A103408 Select[Range[400],PrimeQ[10000#+2101]&] (* _Harvey P. Dale_, Jul 20 2015 *) %o A103408 (Magma) [ n: n in [1..700] | IsPrime(Seqint([1, 0, 1, 2] cat Intseq(n))) ]; // _Vincenzo Librandi_, Feb 03 2011 %o A103408 (PARI) is(n)=isprime(10000*n+2101) \\ _Charles R Greathouse IV_, Jun 06 2017 %Y A103408 Cf. A103118, A102624. %K A103408 base,nonn,easy %O A103408 1,2 %A A103408 _Parthasarathy Nambi_, Mar 20 2005