numbers sequence 10-29-2011

[9974388710035925]

f(1)=0

and

f(n)=4*f(n-1)+13

for every n positive integer from 2 till infinity

the 8th number shown here is 70993,

so the next (9th) number is f(9)=4*70993+13=283985

[hapybrian]

Ah! How can one figure this out?

I said f(1) = 0, and f(2) = 13. Then,

f(n) = f(n-2) + f(n-1) * (8 - n) which worked for the n= 3 and n =4... then fails.

I read the answer on your website, but am wondering what a general method for determining the solution is... Fun stuff!