A098858 Primes p such that floor(sqrt(2)*p) is also a prime.

2, 5, 29, 31, 59, 73, 97, 107, 127, 137, 199, 239, 271, 281, 311, 353, 383, 479, 509, 523, 547, 557, 691, 701, 769, 773, 823, 967, 971, 977, 997, 1049, 1069, 1103, 1117, 1151, 1217, 1367, 1459, 1493, 1523, 1571, 1613, 1663, 1667, 1697, 1783, 1879, 1889, 2011

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

59 and floor(sqrt(2)*59)=83 are primes.

Maple

filter:= proc(p) isprime(p) and isprime(floor(sqrt(2)*p)) end proc:
select(filter, [2, seq(i, i=3..3000, 2)]); # Robert Israel, Sep 04 2019

Mathematica

(* primes that when multiplied by Sqrt[2] give new primes*) digits=1200 a=Delete[Union[Table[If[PrimeQ[Floor[Prime[n]*Sqrt[2]]]==True, Prime[n], 0], {n, 1, digits}]], 1]

Crossrefs

Cf. A001951.

Sequence in context: A344020 A178322 A165161 * A213995 A370513 A134449

Adjacent sequences: A098855 A098856 A098857 * A098859 A098860 A098861

Keyword

nonn

Author

Roger L. Bagula, Oct 11 2004

Status

approved