A081484 - OEIS

A081484

Consider the mapping f(a/b) = (a^2 + b)/(a^2 - b). Taking a =2, b = 1 to start with and carrying out this mapping repeatedly on each new (reduced) rational number gives the following sequence 2/1,5/3,14/11,207/185,... Sequence contains the denominators.

%I #3 Dec 05 2013 19:56:01

%S 1,3,11,185,21332,462959957,107185713294954842,

%T 11488777233793645715382503248255559,

%U 65996001163867589433635003347899702393519681139860824058982662496745

%N Consider the mapping f(a/b) = (a^2 + b)/(a^2 - b). Taking a =2, b = 1 to start with and carrying out this mapping repeatedly on each new (reduced) rational number gives the following sequence 2/1,5/3,14/11,207/185,... Sequence contains the denominators.

%C The mapping f(a/b) = (a + b)/(a - b). Taking a = 2 b = 1 to start with and carrying out this mapping repeatedly on each new (reduced)rational number gives the periodic sequence 2/1,3/1,2/1,3/1,...

%Y Cf. A081483.

%K nonn

%O 1,2

%A _Amarnath Murthy_, Mar 24 2003

%E More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 06 2003