OFFSET
0,2
COMMENTS
Least m>0 for which x^3 - m*y^3 = 1 has a solution with y = n.
LINKS
Robert G. Wilson v, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = A076947(n^3). - Robert Israel, Dec 25 2015
EXAMPLE
17*7^3+1 = 18^3, and 17 is the smallest positive m such that m*7^3+1 is a cube, so a(7)=17.
MATHEMATICA
f[n_] := Block[{x = 2, n3 = n^3}, While[ Mod[x^3 - 1, n3] != 0, x++]; (x^3 - 1)/n3]; f[0] = 1; Array[f, 34, 0] (* Robert G. Wilson v, Mar 24 2016 *)
PROG
(PARI) a(n) = {my(m = 1, cn = n^3); while (!ispower(m*cn + 1, 3), m++); m; } \\ Michel Marcus, Feb 09 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Dec 25 2015
STATUS
approved