A116671 Primes p such that the nearest integer to p * Pi is prime.

13, 17, 31, 53, 71, 73, 101, 181, 197, 223, 229, 239, 241, 281, 311, 313, 353, 367, 491, 521, 607, 821, 859, 863, 919, 1129, 1217, 1303, 1381, 1427, 1471, 1583, 1667, 1721, 1723, 1753, 1811, 1877, 1879, 1933, 1979, 2017, 2063, 2089, 2221, 2399, 2441, 2447

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Example

floor (13Pi + .5) = 41.
floor (17Pi + .5) = 53.

Mathematica

lst={}; Do[p=Prime[n]; If[PrimeQ[Round[p*Pi]], AppendTo[lst, p]], {n, 10^3}]; lst
Select[Prime[Range[400]], PrimeQ[Round[# Pi]]&] (* Harvey P. Dale, Mar 02 2024 *)

Crossrefs

Sequence in context: A129338 A378964 A138535 * A062338 A143863 A158571

Adjacent sequences: A116668 A116669 A116670 * A116672 A116673 A116674

Keyword

nonn,easy

Author

Vladimir Joseph Stephan Orlovsky, Aug 25 2008

Extensions

Edited by Charles R Greathouse IV, Nov 11 2009

Status

approved