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A086085 Primes p such that p + floor(sqrt(p)) is prime. 5
2, 5, 19, 37, 41, 47, 71, 103, 151, 167, 197, 277, 331, 349, 401, 419, 487, 499, 577, 593, 607, 617, 619, 683, 701, 811, 829, 907, 911, 937, 941, 947, 953, 1031, 1061, 1451, 1493, 1511, 1627, 1657, 1669, 1789, 1831, 1847, 1949, 1973, 2161, 2309, 2333, 2341 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..50.

EXAMPLE

a(3)=19 because 19 is prime and 19 + (floor(sqrt(19)) = 19 + (floor(4.358898944)) = 19 + 4 = 23, which is prime.

MATHEMATICA

f[n_]:=Floor[Sqrt[n]]+n; lst={}; Do[p=Prime[n]; If[PrimeQ[f[p]], AppendTo[lst, p]], {n, 7!}]; lst (* Vladimir Joseph Stephan Orlovsky, Feb 25 2010 *)

CROSSREFS

Sequence in context: A090700 A227632 A105889 * A138250 A140761 A077323

Adjacent sequences: A086082 A086083 A086084 * A086086 A086087 A086088

KEYWORD

nonn

AUTHOR

Chuck Seggelin (barkeep(AT)plastereddragon.com), Jul 08 2003

EXTENSIONS

More terms from R. J. Mathar, Oct 31 2008

STATUS

approved

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Last modified December 5 02:30 EST 2022. Contains 358572 sequences. (Running on oeis4.)