OFFSET
1,2
COMMENTS
Erdős (1981) conjectured and Chen and Ruzsa (1999) proved that this constant is irrational.
LINKS
Yong-Gao Chen and Imre Z. Ruzsa, On the irrationality of certain series, Periodica Mathematica Hungarica, Vol. 38, No. 1 (1999), pp. 31-37.
Paul Erdős, Sur l'irrationalité d'une certaine série, C. R. Acad. Sci. Paris, Sér. 1, Vol. 292 (1981), pp. 765-768.
EXAMPLE
1.69790781977962506446424089965347807016709423133847...
MATHEMATICA
RealDigits[Sum[n/2^n, {n, Select[Range[1000], SquareFreeQ]}], 10, 120][[1]]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Amiram Eldar, Mar 12 2024
STATUS
approved