A081479 - OEIS

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

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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