The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A109054 Squares and numbers k such that the continued fraction expansion of sqrt(k) is multiplicative. 2

%I #29 Jul 16 2021 05:22:44

%S 0,1,3,4,7,8,9,13,14,15,16,22,23,24,25,32,33,34,35,36,44,47,48,49,58,

%T 59,60,62,63,64,74,75,78,79,80,81,95,96,98,99,100,114,119,120,121,135,

%U 136,138,140,141,142,143,144,160,162,164,167,168,169,185,187,189,192

%N Squares and numbers k such that the continued fraction expansion of sqrt(k) is multiplicative.

%C If we consider each square k as having a continued fraction expansion c of all zeros after c(0) = sqrt(k)-1, then the continued fraction expansion of sqrt(k) for each square is trivially multiplicative.

%C For nonsquares, c(1) must be 1 and so k must satisfy m + 1/2 < sqrt(k) <= m+1, for some integer m.

%e The continued fraction of sqrt(22) is c = (4; 1, 2, 4, 2, 1, 8, ...) = A010126, which is multiplicative with c(2^e) = 2, c(3^e) = 4, c(p^e) = 1 otherwise.

%Y Union of A000290 and A108575.

%Y Continued fraction expansions: A040001, A010121, A040005, etc.

%K nonn,easy

%O 1,3

%A _Mitch Harris_, Jun 18 2005

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 26 02:45 EDT 2024. Contains 372807 sequences. (Running on oeis4.)