|
|
A154427
|
|
Primes p such that p^2+(p+1)/2 is also prime.
|
|
2
|
|
|
3, 7, 11, 23, 31, 43, 59, 67, 71, 107, 127, 139, 151, 239, 251, 283, 359, 367, 379, 479, 491, 587, 599, 631, 647, 659, 787, 811, 863, 919, 983, 991, 1031, 1063, 1171, 1303, 1319, 1423, 1427, 1483, 1523, 1579, 1583, 1607, 1627, 1723, 1831, 1847, 1907, 1931, 1999
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
The associated primes of the quadratic form are in A164580.
|
|
LINKS
|
|
|
EXAMPLE
|
For p=7, p^2+(p+1)/2=53 is prime, which adds p=7 to the sequence.
|
|
MATHEMATICA
|
Select[Prime[Range[500]], PrimeQ[#^2+(#+1)/2]&]
|
|
PROG
|
(Magma) [p: p in PrimesInInterval(3, 2000) | IsPrime(p^2+(p+1) div 2)]; // Vincenzo Librandi, Oct 12 2012
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|