OFFSET
1,3
COMMENTS
Primes in the sequence occur only once.
REFERENCES
David A. Cox, "Primes of the Form x^2 + n y^2", Wiley, 1989.
EXAMPLE
0 = 0^2+5*0^2,
9 = 2^2+5*1^2 = 3^2+5*0^2,
81 = 1^2+5*4^2 = 6^2+5*3^2 = 9^2+5*0^2,
441: {x,y}={6,9},{11,8},{14,7},{19,4},{21,0}.
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Apr 26 2008
STATUS
approved