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• ... There seems to be a definite pattern to the parity of n*f(n). Try to work from there and see what you can prove about your sequence. Décio [Non-text
Message 1 of 3 , Mar 4, 2005
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On Friday 04 March 2005 15:33, you wrote:
> Define sequence a(n+1)=n*f(n)+a(n), a(1)=2, f(n) is nth term of
> fibonacci sequence. The first few terms are 2,3,7,13,25,73...........
> Notice that all terms except 25 are primes. I think that other terms
> of the sequence are even so I think there will be no more primes. What
> do you think?

There seems to be a definite pattern to the parity of n*f(n). Try to work from

Décio

[Non-text portions of this message have been removed]
• For... f( 1): 1 f( 2): 1 f( 3): 2 f( 4): 3 f( 5): 5 f( 6): 8 f( 7): 13 f( 8): 21 f( 9): 34 f(10): 55 I get... a( 1): 2 a( 2): 3 a( 3): 5 a( 4): 11 a( 5): 23 a(
Message 2 of 3 , Mar 5, 2005
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For...

f( 1): 1
f( 2): 1
f( 3): 2
f( 4): 3
f( 5): 5
f( 6): 8
f( 7): 13
f( 8): 21
f( 9): 34
f(10): 55

I get...

a( 1): 2
a( 2): 3
a( 3): 5
a( 4): 11
a( 5): 23
a( 6): 48
a( 7): 96
a( 8): 187
a( 9): 355
a(10): 661

.....

--- mcnamara_gio <mcnamara_gio@...> wrote:
>
> Define sequence a(n+1)=n*f(n)+a(n), a(1)=2, f(n) is
> nth term of
> fibonacci sequence. The first few terms are
> 2,3,7,13,25,73...........
> Notice that all terms except 25 are primes. I think
> that other terms
> of the sequence are even so I think there will be no
> more primes. What
> do you think?
>
>
>
>

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