A081479 Consider the mapping f(a/b) = (a^2 +b^2)/(a+b). Taking a =1, b = 2 to start with and carrying out this mapping repeatedly on each new (reduced) rational number gives the following sequence 1/2,5/3,17/4,305/21,... Sequence contains the numerators.

1, 5, 17, 305, 46733, 1091999929, 1192463845485813745, 710985011395407339530814550372704577, 252749843214463752223970400013115847462076218642780299149809471303529825

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. A081480.

Sequence in context: A093428 A274002 A286678 * A335313 A318751 A096996

Adjacent sequences: A081476 A081477 A081478 * A081480 A081481 A081482

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