login
A052291
Primes p such that 4p^2 + 1 is also prime.
18
2, 3, 5, 7, 13, 37, 47, 67, 73, 103, 157, 163, 193, 233, 317, 337, 547, 587, 647, 653, 677, 683, 773, 827, 883, 887, 947, 983, 1013, 1063, 1087, 1163, 1297, 1327, 1373, 1487, 1493, 1523, 1553, 1567, 1607, 1627, 1637, 1657, 1663, 1667, 1723, 1867, 1873
OFFSET
1,1
LINKS
Marek Wolf, Search for primes of the form m^2+1, arXiv:0803.1456 [math.NT], 2008-2010.
EXAMPLE
The 5th term is 13 and 4*169+1 = 677 is also a prime.
MATHEMATICA
Select[Prime[Range[300]], PrimeQ[4 #^2 + 1]&] (* Vincenzo Librandi, Apr 11 2013 *)
PROG
(Magma) [p: p in PrimesUpTo(2000) | IsPrime(4*p^2+1)]; // Vincenzo Librandi, Apr 11 2013
CROSSREFS
Cf. A052292.
Sequence in context: A140768 A192578 A050779 * A256072 A072826 A084761
KEYWORD
nonn,easy
AUTHOR
Labos Elemer, Feb 08 2000
STATUS
approved