A368469 a(n) is the sum of exponentially odd divisors of the n-th exponentially odd number.
1, 3, 4, 6, 12, 8, 11, 18, 12, 14, 24, 24, 18, 20, 32, 36, 24, 44, 42, 31, 30, 72, 32, 43, 48, 54, 48, 38, 60, 56, 66, 42, 96, 44, 72, 48, 72, 54, 93, 72, 88, 80, 90, 60, 62, 96, 84, 144, 68, 96, 144, 72, 74, 114, 96, 168, 80, 126, 84, 108, 132, 120, 132, 90, 112
Offset: 1
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Programs
-
Mathematica
f[p_, e_] := 1 + (p^If[OddQ[e], e+2, e+1] - p)/(p^2 - 1); s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; s /@ Select[Range[200], AllTrue[FactorInteger[#][[;; , 2]], OddQ] &] (* or *) f[p_, e_] := If[OddQ[e], 1 + (p^(e + 2) - p)/(p^2 - 1), 0]; s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; Select[Array[s, 200], # > 0 &]
-
PARI
lista(kmax) = {my(f, s, p, e); for(k = 1, kmax, f = factor(k); s = prod(i = 1, #f~, p = f[i,1]; e = f[i,2]; if(e%2, 1 + (p^(e+2) - p)/(p^2 - 1), 0)); if(s > 0, print1(s, ", ")));}