OFFSET
1,1
COMMENTS
REFERENCES
L. E. Dickson, Introduction to the theory of numbers, Dover, NY, 1929.
J. M. Borwein and P. B. Borwein, Pi and the AGM, page 293.
FORMULA
PROG
(PARI) ok(n)={n<>1 && n%4==1 && issquarefree(n) && !select(t->t<>2, quadclassunit(-4*n).cyc)} \\ Andrew Howroyd, Jun 09 2018
CROSSREFS
KEYWORD
nonn,fini,full
AUTHOR
Jonathan Borwein (jborwein(AT)cecm.sfu.ca), Stephen Choi (choi(AT)cecm.sfu.ca)
STATUS
approved