OFFSET
1,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..10000
EXAMPLE
a(9)=4 because 9*4=36 can be factored as 36=18*2=2*18=6*6.
MAPLE
with(numtheory):
b:= proc(n) option remember; 1+add(`if`(irem(d, 2)=0 and
irem(n/d, 2)=0, b(d), 0), d=divisors(n) minus {1, n})
end:
a:= n-> b(4*n):
seq(a(n), n=1..100); # Alois P. Heinz, Feb 17 2015
MATHEMATICA
nn = 300; f[list_, i] := list[[i]]; a = Table[Boole[EvenQ[n]], {n, 1, nn}]; Select[Map[Total, Transpose[NestList[Table[DirichletConvolve[f[#, n], f[a, n], n, m], {m, 1, nn}] &, a, nn]]], # > 1 &] (* Geoffrey Critzer, Feb 17 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Christian G. Bower, Jun 06 2005
STATUS
approved