cp's OEIS Frontend

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.

A216133 In the decimal expansion of Pi, the first occurrence of these primes begins at a prime position.

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%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