A224796 Pi*n rounded to the nearest integer is prime.

1, 4, 6, 10, 13, 15, 17, 25, 31, 32, 34, 36, 48, 50, 52, 53, 55, 57, 71, 73, 76, 80, 90, 99, 101, 111, 122, 134, 141, 143, 155, 160, 162, 174, 181, 187, 195, 197, 201, 204, 206, 208, 220, 223, 229, 239, 241, 246, 258, 262, 264, 267, 279, 281, 290, 309, 311, 313

Offset

1,2

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Chris Caldwell and G. L. Honaker, Jr., Prime curio for 15

Example

a(3)=6 because Pi*6 = 18.849559..., which rounds to 19 (a prime number).

Mathematica

Select[Range[350], PrimeQ[Round[Pi #]]&] (* Harvey P. Dale, Oct 10 2024 *)

Prog

(PARI) is(n)=isprime(round(Pi*n)) \\ Charles R Greathouse IV, Apr 18 2013

Crossrefs

Cf. A000040, A000796, A224719.

Sequence in context: A086493 A234965 A320881 * A190370 A246439 A186514

Adjacent sequences: A224793 A224794 A224795 * A224797 A224798 A224799

Keyword

nonn

Author

G. L. Honaker, Jr., Apr 18 2013

Extensions

Additional terms from Mike Keith (mikek314(at)gmail.com), Apr 18 2013

Status

approved