380 History of the Theory of Numbers. [Chap, xv 
A. G^rardin" noted that F„ = (240j+97)(240!/+161) for all the F„ 
fully factored to date, and specified x and y more exactly in special cases. 
C. Henrv'^'- gave references and quoted known results. 
R. D. CannichaeP' gave a test for the primality of F„ equivalent to 
Pepin's^^ and a further generalization (p. 65) in the direction of Hurwitz's." 
R. C. Archibald" cited many of the papers hsted above and collected in a 
table the known factors of F„ with the exception of that given by Morehead." 
For a remark on F„, see Cunningham^°^ of Ch. VII. 
"Sphinx-Oedipe, 7, 1912, 13. 
•HDeuvres de Fermat, 4, 1912, 202-4. 
"Annals of Math., (2), 15, 1913-4, 67. 
•'Amer. Math. Monthly, 21. 1914. 247-251. 
