OFFSET
1,3
COMMENTS
This constant is irrational (Golomb, 1973).
LINKS
Solomon W. Golomb, A new arithmetic function of combinatorial significance, Journal of Number Theory, Vol. 5, No. 3 (1973), pp. 218-223.
EXAMPLE
1.06838993007841232002084765901758238224728960865528...
MATHEMATICA
f[n_] := DivisorSigma[0, GCD @@ FactorInteger[n][[;; , 2]]]; RealDigits[Sum[f[n]/2^n, {n, 1, 1000}], 10, 100][[1]]
PROG
(PARI) 1/2 + suminf(k=2, numdiv(gcd(factor(k)[, 2]))/2^k) \\ Michel Marcus, Jul 16 2021
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Amiram Eldar, Jul 15 2021
STATUS
approved