OFFSET
0,6
EXAMPLE
n=14 k=42 (14^3 * 42^3)/(14^3 + 42^3)= (2744 * 74088)/(2744 + 74088) = 203297472 / 76832 = 2646
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paolo P. Lava and Giorgio Balzarotti, Jun 05 2006
STATUS
approved