OFFSET
1,3
FORMULA
Sum_{i = 2^k..2^(k + 1) - 1} a(i) = 5*2^(k - 1) - 2, for k >= 1.
a(2^k) = 1.
EXAMPLE
MATHEMATICA
a[1] = 1; a[n_] := a[n] = If[EvenQ[n], DivisorSigma[0, a[n/2]], DivisorSigma[0, a[(n - 1)/2]] + 1]; Array[a, 100] (* Amiram Eldar, Dec 25 2022 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Ctibor O. Zizka, Dec 25 2022
STATUS
approved