N********n
发帖数: 8363 | 1 rt, given a number, how to quickly detect that? Heard there's a
fast way to do that. Any one knows? | f******k
发帖数: 297 | 2 let the number be N, then N is a fibonacci number iff
5*N^2+4 or 5*N^2-4 is a square of an integer.
【在 N********n 的大作中提到】
: rt, given a number, how to quickly detect that? Heard there's a
: fast way to do that. Any one knows?
| N********n
发帖数: 8363 | 3
I see. Thanks!!
【在 f******k 的大作中提到】
: let the number be N, then N is a fibonacci number iff
: 5*N^2+4 or 5*N^2-4 is a square of an integer.
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