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A005042
Primes formed by the initial digits of the decimal expansion of Pi.
(Formerly M3129)
30
3, 31, 314159, 31415926535897932384626433832795028841
OFFSET
1,1
COMMENTS
The next term consists of the first 16208 digits of Pi and is too large to show here (see A060421). Ed T. Prothro found this probable prime in 2001.
A naive probabilistic argument suggests that the sequence is infinite. - Michael Kleber, Jun 23 2004
REFERENCES
M. Gardner, personal communication.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
FORMULA
a(n) = floor(10^(A060421(n)-1)*A000796), where A000796 is the constant Pi = 3.14159... . - M. F. Hasler, Sep 02 2013
MAPLE
Digits := 130; n0 := evalf(Pi); for i from 1 to 120 do t1 := trunc(10^i*n0); if isprime(t1) then print(t1); fi; od:
MATHEMATICA
a = {}; Do[k = Floor[Pi 10^n]; If[PrimeQ[k], AppendTo[a, k]], {n, 0, 160}]; a (* Artur Jasinski, Mar 26 2008 *)
nn=1000; With[{pidigs=RealDigits[Pi, 10, nn][[1]]}, Select[Table[FromDigits[ Take[pidigs, n]], {n, nn}], PrimeQ]] (* Harvey P. Dale, Sep 26 2012 *)
PROG
(PARI) c=Pi; for(k=0, precision(c), isprime(c\.1^k) & print1(c\.1^k, ", ")) \\ - M. F. Hasler, Sep 01 2013
CROSSREFS
See A060421 for further terms.
Sequence in context: A118913 A297480 A282973 * A367038 A317482 A136582
KEYWORD
nonn,base
STATUS
approved