OFFSET
1,1
LINKS
T. D. Noe, Table of n, a(n) for n=1..1000
EXAMPLE
a(1) = 31 = 2^1 * 3^1 * 5^1 + 1.
a(2) = 61 = 2^2 * 3^1 * 5^1 + 1.
a(3) = 151 = 2^1 * 3^1 * 5^2 + 1.
a(4) = 181 = 2^2 * 3^2 * 5^1 + 1.
Values include 30000001 = 2^7 * 3^1 * 5^7 + 1, 90000000001 = 2^9 * 3^2 * 5^9 + 1.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post, Feb 22 2006
STATUS
approved