A081483 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 numerator.

2, 5, 14, 207, 21517, 463002621, 107185713757914799, 11488777233793645929753929838165243, 65996001163867589433635003347899713882296914933506539441485910752304

Offset

1,1

Comments

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,...

Links

Table of n, a(n) for n=1..9.

Crossrefs

Cf. A081484.

Sequence in context: A284661 A097595 A243979 * A118478 A179675 A193314

Adjacent sequences: A081480 A081481 A081482 * A081484 A081485 A081486

Keyword

nonn

Author

Amarnath Murthy, Mar 24 2003

Extensions

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

Status

approved