OFFSET
1,2
EXAMPLE
1.29134317210725954613882...
MAPLE
with(numtheory);
P:=proc(i)
local a, f, n, p, pfs;
a:=1;
for n from i by -1 to 2 do
pfs:=ifactors(n)[2];
f:=n*add(op(2, p)/op(1, p), p=pfs) ;
a:=f*sqrt(a);
od;
print(evalf(sqrt(a), 150));
end:
P(500);
MATHEMATICA
digits = 105; d[0] = d[1] = 0; d[n_] := d[n] = n*Total[Apply[#2/#1 &, FactorInteger[n], {1}]]; f[n_] := f[n] = Fold[Sqrt[d[#2]*#1]&, n, Range[n-1, 2, -1]] // RealDigits[#, 10, digits]& // First; f[digits]; f[n = 2*digits]; While[f[n] != f[n/2], n = 2*n]; f[n] (* Jean-François Alcover, Feb 21 2014 *)
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Paolo P. Lava, May 05 2011
STATUS
approved