OFFSET
1,1
EXAMPLE
a(5)=9 because 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 = 81 = 3^4, 9 consecutive integers are needed.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jason Earls, Jul 17 2005
STATUS
approved