OFFSET
1,2
FORMULA
a(n) = Sum_{k=1..n} rad(k)*rad(n+1-k) where rad = A007947 is the product of the distinct prime factors of n.
MAPLE
read("transforms") ;
a007947 := [seq(A007947(n), n=1..60)] ;
CONV(a007947, a007947) ; # R. J. Mathar, Nov 07 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Aug 10 2010
STATUS
approved