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.

1, 3, 11, 185, 21332, 462959957, 107185713294954842, 11488777233793645715382503248255559, 65996001163867589433635003347899702393519681139860824058982662496745

Offset

1,2

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. A081483.

Sequence in context: A118479 A103836 A284704 * A125738 A334176 A332771

Adjacent sequences: A081481 A081482 A081483 * A081485 A081486 A081487

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