--- leavemsg1 <

leavemsg1@...> wrote:

> Is it entirely obvious that 2^(p-1)+3^(p-2) -1 is always divisible by 2

> and 3 where p is prime???

Humans and mail are slow. Computers and Pari/GP are fast.

? for(i=2,12,print(i" : "2^(i-1)%6" "3^(i-2)%6" "(2^(i-1)+3^(i-2))%6))

2 : 2 1 3

3 : 4 3 1

4 : 2 3 5

5 : 4 3 1

6 : 2 3 5

7 : 4 3 1

8 : 2 3 5

9 : 4 3 1

10 : 2 3 5

11 : 4 3 1

12 : 2 3 5

So it's not just true when p's an (odd) prime, but true whenever p's any odd

number.

Phil

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