OFFSET
0,1
COMMENTS
Apparently discovered (with arbitrary base) by Gottschalk in 1938 and independently by Ferentinou-Nicolacopoulou in 1963. - Charles R Greathouse IV, Jul 05 2011
REFERENCES
J. Ferentinou-Nicolacopoulou, "Une propriété des diviseurs du nombre r^(r^m)+1. Applications au dernier théorème de Fermat." Bulletin Société Mathématique de Grèce 4:1 (1963), pp. 121-126.
LINKS
Eugen Gottschalk, Zum Fermatschen Problem, Mathematische Annalen 115 (1934), pp. 157-158.
Lorenzo Sauras-Altuzarra, Some properties of the factors of Fermat numbers, Art Discrete Appl. Math. (2022).
FORMULA
a(n) = 3^(3^n) + 1. a(n) = A055777(n) + 1.
MATHEMATICA
Table[3^3^n+1, {n, 0, 6}]
PROG
(PARI) a(n)=3^(3^n)+1 \\ Charles R Greathouse IV, Jul 05 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Alexander Adamchuk, Apr 08 2007
STATUS
approved