OFFSET
1,1
COMMENTS
LINKS
Jon Maiga, Table of n, a(n) for n = 1..1000
EXAMPLE
The actual solutions are 4, 8, 10, 14, 16, 20, 22, 28, 32, 38, 40, 44, 46, 52, 58, 62, 68, 70, 74, 80, 82, 88, 98, 100, 104, 106, 110, 112, 128, 130, 136, 140, 148, 152, 158, 164, 166, 172, 178, 182, 190, 194, 196, 200, 212, 224, 226, 230, ...
n=4: 2*a(4) = 14 = 3*13 - 25. 14^2 = 196 == 1 (mod 39), 25^2 = 625 == 1 (mod 39). Representatives of the trivial solutions are 1 and 39-1= 38. All-together there are 4 incongruent solutions.
MATHEMATICA
Table[(3*Prime[n+2]-SelectFirst[Solve[x^2==1 && x !=1, x, Modulus->3*Prime[n+2]][[All, 1, 2]], OddQ])/2, {n, 50}] (* Jon Maiga, Sep 28 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Wolfdieter Lang, Mar 14 2012
STATUS
approved