OFFSET
1,2
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..250
G. Villemin's Almanach of Numbers, Sum of Four cubes:Multiple Representations
EXAMPLE
a(3) = 856 because the latter is the smallest number expressible as the sum of four cubes in 3 distinct ways, namely 856 = 0^3 + 1^3 + 7^3 + 8^3 = 1^3 + 1^3 + 5^3 + 9^3 = 4^3 + 4^3 + 6^3 + 8^3.
PROG
(PARI) mx=10^7; v=vector(mx+1); cb=vector(216); for(j=0, 215, cb[j+1]=j^3); for(j1=1, 136, for(j2=j1, 150, s2=cb[j1]+cb[j2]; for(j3=j2, 171, s3=s2+cb[j3]; if(s3+cb[j3]>mx, next(2)); for(j4=j3, 216, s4=s3+cb[j4]; if(s4>mx, next(2)); v[s4+1]++)))); for(n=1, 68, for(j=1, mx+1, if(v[j]==n, print(n " " j-1); next(2)))) /* Donovan Johnson, Apr 16 2013 */
CROSSREFS
KEYWORD
nonn
AUTHOR
Lekraj Beedassy, Nov 12 2002
EXTENSIONS
More terms from Jon E. Schoenfield, Jul 23 2006
STATUS
approved