OFFSET
0,2
FORMULA
a(0) = 0 and a(1) = 3, a(n) = a(n-1) + (a(n-1)^5 - 5) mod 7^n for n > 1.
EXAMPLE
a(1) = ( 3)_7 = 3,
a(2) = ( 63)_7 = 45,
a(3) = ( 663)_7 = 339,
a(4) = (3663)_7 = 1368.
PROG
(PARI) {a(n) = truncate((5+O(7^n))^(1/5))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Aug 03 2019
STATUS
approved