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!)
A059514 For a rational number p/q let f(p/q) = p*q divided by (the sum of digits of p and of q) minus 1; a(n) is obtained by iterating f, starting at n/1, until an integer is reached, or if no integer is ever reached then a(n) = 0. 2
1, 1, 1, 1, 1, 1, 1, 1, 1, 10, 11, 4, 28, 42, 7315, 208, 136, 2, 19, 10, 7, 11, 69, 4, 2310, 28, 3, 42, 319, 10, 189885850, 96, 11, 323323, 205530, 4, 37, 228, 28, 10, 123, 7, 559, 11, 5, 69, 517, 4, 152152, 10, 187, 28, 424, 6, 11, 154, 0, 77140, 2478, 10, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,10
COMMENTS
a(A216183(n)) = 0. - Reinhard Zumkeller, Mar 11 2013
LINKS
EXAMPLE
14/1 -> 14/5 -> 70/9 -> 630/15 = 42 so a(14)=42.
57/1 -> 19/4 -> 76/13 -> 247/4 -> 247/4 -> ... so a(57) = 0.
PROG
(Haskell)
import Data.Ratio ((%), numerator, denominator)
a059514 n = f [n % 1] where
f xs@(x:_)
| denominator y == 1 = numerator y
| y `elem` xs = 0
| otherwise = f (y : xs)
where y = (numerator x * denominator x) %
(a007953 (numerator x) + a007953 (denominator x) - 1)
-- Reinhard Zumkeller, Mar 11 2013
CROSSREFS
Cf. A007953.
Sequence in context: A289985 A065517 A235600 * A066355 A071206 A066577
KEYWORD
base,easy,nonn
AUTHOR
Floor van Lamoen, Jan 22 2001
EXTENSIONS
Corrected and extended by Naohiro Nomoto, Jul 20 2001
STATUS
approved

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 March 28 10:55 EDT 2024. Contains 371241 sequences. (Running on oeis4.)