OFFSET
1,3
COMMENTS
Also, smallest number k such that n! - k is a cube.
Sequence is not monotonic: a(n) < a(n-1) for n: 7, 14, 25, 30, 51, 106, 168, 279, 288.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..500
EXAMPLE
a(2) = 2! - 1^3 = 1, a(3) = 3! - 1^3 = 5, a(4) = 4! - 3^3 = 16.
MATHEMATICA
Join[{1}, Table[n! - Floor[(n!)^(1/3)]^3, {n, 2, 30}]]
PROG
(PARI) a(n)=my(N=n!); N-sqrtnint(N, 3)^3 \\ Charles R Greathouse IV, Jun 25 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Jun 25 2013
STATUS
approved