OFFSET
0,2
FORMULA
(4^n - 1)^n
EXAMPLE
a(3) = 63^3 = 250047.
PROG
(PARI) a(n) = (4^n - 1)^n; \\ Michel Marcus, Apr 16 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Hannah Ko, Apr 15 2014
STATUS
approved