OFFSET
1,1
COMMENTS
100Q^2-5 always has a prime divisor congruent to 9 modulo 10.
LINKS
Robert Price, Table of n, a(n) for n = 1..14
EXAMPLE
a(3) = 462739 is the smallest prime divisor congruent to 9 mod 10 of 100Q^2-5 = 1881313992095 = 5 * 462739 * 813121, where Q = 19 * 7219.
MATHEMATICA
a={19}; q=1;
For[n=2, n<=6, n++,
q=q*Last[a];
AppendTo[a, Min[Select[FactorInteger[100*q^2-5][[All, 1]], Mod[#, 10]==9&]]];
];
a (* Robert Price, Jul 18 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Nick Hobson, Nov 18 2006
STATUS
approved