A284036 Positive integers n such that (n^2 - 3)/2 and (n^2 + 1)/2 are twin primes.
3, 5, 11, 19, 25, 29, 65, 79, 101, 205, 209, 221, 245, 275, 289, 299, 349, 371, 409, 415, 449, 521, 535, 569, 571, 575, 595, 649, 661, 695, 739, 781, 791, 935, 949, 991, 1081, 1091, 1099, 1129, 1181, 1225, 1241, 1285, 1345, 1349, 1459, 1489, 1531, 1541, 1615
Offset: 1
Keywords
Examples
25 is a term because (25^2 - 3)/2 = 311 and (25^2 + 1)/2 = 313 are twin primes.
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Programs
-
Maple
filter:= n -> isprime((n^2-3)/2) and isprime((n^2+1)/2): select(filter, [seq(i,i=1..2000,2)]); # Robert Israel, Apr 24 2017
-
Mathematica
Select[Range[1, 1285, 2], Times @@ Boole@ Map[PrimeQ, (#^2 + {-3, 1})/2] == 1 &] (* Michael De Vlieger, Mar 28 2017 *) -
PARI
isok(n) = isprime((n^2 - 3)/2) && isprime((n^2 + 1)/2); \\ Michel Marcus, Apr 04 2017
-
Python
from sympy import isprime print([n for n in range(3, 1700, 2) if isprime((n**2 - 3)//2) and isprime((n**2 + 1)//2)]) # Indranil Ghosh, Apr 04 2017
-
Sage
[n for n in range(3,1700,2) if is_prime((n^2 - 3)//2) and is_prime((n^2 + 1)//2)]
Comments