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 A065570 #12 Apr 11 2021 16:12:10
%S A065570 264,274,322,751,3112,24842,32731
%N A065570 Numbers k such that the first k ternary digits found in the decimal expansion of Pi form a prime.
%t A065570 p = First[ RealDigits[ Pi, 10, 10^5]]; p = p[[ Select[ Range[10^5], p[[ # ]] == 0 || p[[ # ]] == 1 || p[[ # ]] == 2 & ]]]; Do[ If[ PrimeQ[ FromDigits[ Take[p, n], 3]], Print[n]], {n, 1, 4000} ]
%t A065570 Module[{nn=30000,pd},pd=Select[RealDigits[Pi,10,nn][[1]],#<3&];Select[ Range[ Length[pd]],PrimeQ[FromDigits[Take[pd,#],3]]&]] (* The program generates the first five terms of the sequence. To generate more, increase the constant for "nn," but it will take a long time to run and the value of nn may be to be 150,000 or more. *) (* _Harvey P. Dale_, Jul 31 2020 *)
%Y A065570 Cf. A065832.
%K A065570 nonn,base
%O A065570 1,1
%A A065570 _Robert G. Wilson v_, Nov 30 2001
%E A065570 a(6)-a(7) from _Chai Wah Wu_, Apr 07 2020