

A163848


Primes p such that the differences between p and the closest squares surrounding p are primes.


2



7, 11, 23, 47, 83, 167, 227, 443, 1223, 1367, 1847, 2027, 3023, 3251, 5039, 5927, 9803, 11447, 13691, 14639, 16127, 21611, 24023, 36479, 44519, 47087, 49727, 50627, 54287, 61007, 64007, 65027, 88211, 90599, 95483, 103043, 104327, 123203, 137639
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000


EXAMPLE

74=3, 97=2; 119=2, 1611=5; 2316=7, 2523=2; ..


MATHEMATICA

Clear[f, lst, p, n]; f[n_]:=IntegerPart[Sqrt[n]]; lst={}; Do[p=Prime[n]; If[PrimeQ[pf[p]^2]&&PrimeQ[(f[p]+1)^2p], AppendTo[lst, p]], {n, 8!}]; lst
spQ[n_]:=Module[{lsq=Floor[Sqrt[n]]}, And@@PrimeQ[{nlsq^2, (lsq+1)^2n}]]; Select[Prime[Range[140000]], spQ] (* Harvey P. Dale, May 08 2011 *)


PROG

(PARI) forstep(n=3, 1e6, 2, if(isprime(2*n3)&&isprime(k=n^22), print1(k", ")); if(isprime(2*n1)&&isprime(k=n^2+2), print1(k", ")))


CROSSREFS

Sequence in context: A107133 A079138 A319135 * A111671 A213895 A140111
Adjacent sequences: A163845 A163846 A163847 * A163849 A163850 A163851


KEYWORD

nonn


AUTHOR

Vladimir Joseph Stephan Orlovsky, Aug 05 2009


EXTENSIONS

Program and editing by Charles R Greathouse IV, Nov 02 2009


STATUS

approved



