login
A067559
Numbers n such that floor(Pi*n^2) is prime.
3
1, 6, 17, 31, 34, 41, 45, 50, 51, 61, 69, 73, 74, 81, 103, 108, 111, 142, 148, 175, 192, 201, 202, 203, 232, 234, 273, 277, 281, 310, 319, 329, 342, 348, 349, 351, 378, 387, 416, 421, 428, 435, 459, 478, 486, 521, 526, 575, 593, 597, 603, 605, 623, 648, 661
OFFSET
1,2
LINKS
EXAMPLE
Floor[Pi*6^2] = 113, a prime, so 6 is a term of the sequence.
MATHEMATICA
Select[Range[1, 10^3], PrimeQ[Floor[Pi * #^2]] &]
PROG
(PARI) is(n)=isprime(floor(Pi*n^2)) \\ Charles R Greathouse IV, May 22 2017
CROSSREFS
Cf. A062408.
Sequence in context: A063230 A212461 A204059 * A096426 A130051 A338894
KEYWORD
easy,nonn
AUTHOR
Joseph L. Pe, Jan 29 2002
STATUS
approved