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 A101780 #12 Apr 03 2023 10:36:10
%S A101780 3,103,503,1103,1303,2003,2203,2503,2803,2903,3203,3803,4003,4603,
%T A101780 4703,4903,5003,5303,5503,5903,6203,6703,6803,7103,7603,7703,8803,
%U A101780 9103,9203,9403,9803,10103,10303,10903,11003
%N A101780 Primes of the form 100*n + 3.
%H A101780 Vincenzo Librandi, <a href="/A101780/b101780.txt">Table of n, a(n) for n = 1..1000</a>
%H A101780 Chris K. Caldwell <a href="https://t5k.org/lists/small/100000.txt">The first 100,008 primes</a>.
%t A101780 100*Select[Range[0, 200], PrimeQ[100# + 3] &] + 3 (* _Stefan Steinerberger_, Feb 28 2006 *)
%t A101780 Select[Table[100*n+3,{n,0,700}],PrimeQ] (* _Vincenzo Librandi_, Jul 19 2012 *)
%o A101780 (Magma) [a: n in [0..250]|IsPrime(a) where a is 100*n+3]; // _Vincenzo Librandi_, Jul 19 2012
%K A101780 nonn,easy
%O A101780 1,1
%A A101780 _Parthasarathy Nambi_, Jan 26 2005
%E A101780 More terms from _Stefan Steinerberger_, Feb 28 2006