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 A198019 #14 Jul 22 2020 11:35:43
%S A198019 3,31,41,5,59,4159,14159,314159,2,53,653,1592653,89,141592653589,7,97,
%T A198019 5897,35897,6535897,5926535897,415926535897,79,58979,358979,589793,23,
%U A198019 9323,9265358979323,43,643,462643,93238462643,433,83,383,2643383,38462643383,89793238462643383,41592653589793238462643383
%N A198019 Primes occurring in the decimal expansion of Pi (A000796), ordered by position of last digit, then by size.
%C A198019 Cf. A198018; the only difference is that here we list the "new primes" by increasing size (for a given subsequence of A000796).
%C A198019 Considering the first 1, 2, 3, 4,.... digits of the decimal expansion 3.14159... of Pi, record the primes that have not occurred earlier.
%C A198019 Sequence A198187 lists "duplicate" primes multiple times, each time they occur anew ending in another decimal place. - _M. F. Hasler_, Sep 01 2013
%e A198019 In Pi = 3... we have the prime a(1)=3.
%e A198019 In Pi = 3.1.... we have the prime a(2)=31.
%e A198019 In Pi = 3.14... we have no new prime.
%e A198019 In Pi = 3.141.... we have the prime a(3)=41.
%e A198019 In Pi = 3.1415.... we have the new prime a(5)=5.
%e A198019 In Pi = 3.14159.... we have the new primes (listed in increasing order) a(6)=59, a(7)=4159, a(8)=14159 and a(9)=314159. [_M. F. Hasler_, Sep 01 2013]
%o A198019 (PARI) {t=Pi; u=[]; for(i=0,precision(t), for(k=1,i+1, ispseudoprime(p=t\.1^i%10^k)& !setsearch(u,p)& (u=setunion(u,Set(p)))&print1(p",")))}
%Y A198019 Cf. A000796, A198018.
%Y A198019 Cf. A047777, A053013, A064467.
%K A198019 nonn,base
%O A198019 1,1
%A A198019 _M. F. Hasler_, Oct 20 2011