I'm not sure how to go about setting up the steps for this problem.

a1 = 1, a2 = 1 and an = 2an-1 + an-2 for all n ≥ 3. prove an is odd for all n≥1.

first six are 1,1,3,7,17,41

I could also use help on another problem...

proving (3,5,7) is the only prime triple - consecutive odd integers which are all prime -

to do this i prove that for any odd integer k, one of the integers 2k+1, 2k+3, and 2k+5 must be divisible by 3.

I know i need to use cases for this.

how does this then show that (3,5,7) is the only prime triple?

thanks for the input guys.

kyle