OFFSET
0,2
FORMULA
a(n) = SUM[d|n] d*(d+1)*(d+2)*(d+3)*(d+4)*(d+5)/720. a(n) = SUM[d|n] C(d,6). a(n) = SUM[d|n] A000579(d). a(n) = SUM[d|n] (1/720)d^6+(1/48)d^5+(17/144)d^4+(5/16)d^3+(137/360)d^2+(1/6)d.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post, Apr 02 2006
STATUS
approved