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A243629
Fibonacci's solution to x^3 + 2x^2 + 10x = 20.
2
1, 22, 7, 42, 33, 4, 40
OFFSET
0,2
COMMENTS
Fibonacci attempted to solve x^3 + 2x^2 + 10x = 20 and managed to approximate an answer in base 60 with this sequence without a calculator or computer, but he gave a(6) as 40 instead of the correct answer of 38 (see A159990). Unfortunately, Fibonacci did not explain how he calculated this sequence, so it is not possible to explore the precision to a greater degree.
REFERENCES
Alfred S. Posamentier & Ingmar Lehmann, The (Fabulous) Fibonacci Numbers. New York: Prometheus Books (2007): 21.
EXAMPLE
x = 1 + 22/60 + 7/60^2 + 42/60^3 + 33/60^4 + 4/60^5 + 40/60^6. Then x^3 + 2x^2 + 10x = 20.0000000006719323...
CROSSREFS
Cf. A159990 shows the sequence corrected.
Sequence in context: A194708 A069285 A159990 * A040466 A133682 A134911
KEYWORD
nonn
AUTHOR
Jason Chabora, Jun 10 2014
STATUS
approved