OFFSET
1,2
COMMENTS
Differs from A030691.
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = (A138174(n))^(1/3).
PROG
(Sage)
A138173 = lambda n: next(m for m in IntegerRange(1, infinity) if str(m**3).startswith(str(n**2)))
# D. S. McNeil, Dec 12 2010
(Python)
from gmpy2 import iroot
def A138173(n):
d, nd = 1, n**2
while True:
x = iroot(nd-1, 3)[0]+1
if x**3 < nd+d:
return int(x)
d *= 10
nd *= 10 # Chai Wah Wu, May 24 2016
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Mar 05 2008
STATUS
approved