OFFSET
1,2
COMMENTS
Note that if m appears in the sequence then k^3*m will also appear for all k and so in particular all cubes appear; the reverse is not always true (for example, 32*255*257/60 = 34952 = 2^3*4369 eventually appears, but 4369 does not).
By considering the Pythagorean triangle (3k, 4k, 5k) we see that all numbers k^3 are in the sequence. - Sergey Pavlov, Mar 29 2017
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..386
EXAMPLE
a(1) = 3*4*5/60 = 1.
MATHEMATICA
(k=600000; lst={}; Do[Do[If[IntegerQ[a=Sqrt[c^2 - b^2]], If[a>=b, Break[]]; x=a b c; If[x<=k, AppendTo[lst, x]]], {b, c - 1, 4, -1}], {c, 5, 400, 1}]; Union@lst)/60 (* Vincenzo Librandi Mar 30 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Henry Bottomley, Aug 01 2000
STATUS
approved