The On-Line Encyclopedia of Integer Sequences (OEIS)

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A173827

Primes p such that p+(floor(Sqrt(p)))^2 is prime.
(history; published version)

#4 by Harvey P. Dale at Wed Apr 24 09:07:33 EDT 2013

STATUS

editing

approved

#3 by Harvey P. Dale at Wed Apr 24 09:07:17 EDT 2013

MATHEMATICA

Select[Prime[Range[400]], PrimeQ[#+Floor[Sqrt[#]]^2]&] (* Harvey P. Dale, Apr 24 2013 *)

STATUS

approved

editing

#2 by Russ Cox at Sat Mar 31 12:38:28 EDT 2012

AUTHOR

_Vladimir Joseph Stephan Orlovsky (4vladimir(AT)gmail.com), _, Feb 25 2010

Discussion

Sat Mar 31

12:38

OEIS Server: https://oeis.org/edit/global/876

#1 by N. J. A. Sloane at Tue Jun 01 03:00:00 EDT 2010

NAME

Primes p such that p+(floor(Sqrt(p)))^2 is prime.

DATA

2, 7, 37, 43, 47, 67, 73, 149, 163, 167, 223, 337, 349, 353, 359, 409, 421, 439, 487, 499, 577, 587, 617, 691, 787, 823, 829, 911, 947, 1039, 1063, 1087, 1201, 1297, 1321, 1361, 1367, 1453, 1459, 1483, 1609, 1621, 1657, 1777, 1783, 1987, 1993, 2011, 2137, 2143

OFFSET

1,1

COMMENTS

2+1=3 prime, 7+4=11 prime, 37+36=73 prime,...

MATHEMATICA

f[n_]:=n+(Floor[Sqrt[n]])^2; lst={}; Do[p=Prime[n]; If[PrimeQ[f[p]], AppendTo[lst, p]], {n, 7!}]; lst

CROSSREFS

Cf. A086085, A086086, A135932, A173826

KEYWORD

nonn

AUTHOR

Vladimir Orlovsky (4vladimir(AT)gmail.com), Feb 25 2010

STATUS

approved