OFFSET
1,1
COMMENTS
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..5000
FORMULA
a(n) = (-3 + sqrt(9 + 12*(A225909(n) - 1)))/6
EXAMPLE
(5+1)^3 - 5^3 = 3^3 + 4^3, so 5 is a member.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Sondow, Jun 21 2013
STATUS
approved