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A216133
In the decimal expansion of Pi, the first occurrence of these primes begins at a prime position.
0
7, 19, 31, 41, 43, 79, 89, 107, 137, 157, 197, 233, 263, 271, 293, 317, 367, 379, 433, 449, 479, 491, 499, 601, 641, 653, 673, 751, 757, 761, 769, 787, 797, 821, 823, 827, 853, 887
OFFSET
1,1
COMMENTS
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.
EXAMPLE
The first 19 in the decimal expansion of Pi (see A000796) starts in position 37, which is a prime.
MATHEMATICA
pos_in_Pi={1, 6, 9, 2, 4, 7, 13, 11, 5, 49, 94, 148, 110, 1, 3, ....};
s={}; Do[If[PrimeQ[x]&&PrimeQ[pos_in_Pi[[x]]], AppendTo[s, pos_in_Pi]], {x, Length[v]}]; s
CROSSREFS
Cf. A000796.
Sequence in context: A040045 A242476 A079021 * A079740 A030549 A017605
KEYWORD
nonn,base
AUTHOR
EXTENSIONS
Edited by N. J. A. Sloane, Sep 09 2012
STATUS
approved