[seqfan] Re: sequence from a test A171371

[Jeremy Gardiner]

Wow, that is a pretty severe mental arithmetic test!

On 7/12/09 05:53, "Alexander Povolotsky" <apovolot at gmail.com> wrote:
 
so explicit formula appears to be

a(n)=  -15/8 * (3-sqrt(17))^n-15/8 * (3+sqrt(17))^n+77/136 * (3+sqrt(17))^n
* sqrt(17)-77/136 * (3-sqrt(17))^n*sqrt(17)
 
--- On Sun, 12/6/09, N. J. A. Sloane <njas at research.att.com> wrote:
 
I don't know the pattern to this sequence yet, but it appears on
mental-testing.com.