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 A216133 #7 Oct 01 2012 12:16:25 %S A216133 7,19,31,41,43,79,89,107,137,157,197,233,263,271,293,317,367,379,433, %T A216133 449,479,491,499,601,641,653,673,751,757,761,769,787,797,821,823,827, %U A216133 853,887 %N A216133 In the decimal expansion of Pi, the first occurrence of these primes begins at a prime position. %C A216133 We label the positions in 3.14159... so that 1 is in position 1, 4 in position 2, 1 in position 3, 5 in position 4, and so on. %e A216133 The first 19 in the decimal expansion of Pi (see A000796) starts in position 37, which is a prime. %t A216133 pos_in_Pi={1,6,9,2,4,7,13,11,5,49,94,148,110,1,3,....}; %t A216133 s={};Do[If[PrimeQ[x]&&PrimeQ[pos_in_Pi[[x]]],AppendTo[s,pos_in_Pi]],{x,Length[v]}];s %Y A216133 Cf. A000796. %K A216133 nonn,base %O A216133 1,1 %A A216133 _Vicente Izquierdo Gomez_, Sep 01 2012 %E A216133 Edited by _N. J. A. Sloane_, Sep 09 2012