[seqfan] Re: Confused by Collatz-Fibonacci numbers

[Eric Schmidt]

On 4/2/2015 8:48 PM, Alonso Del Arte wrote:
> I'm still perplexed by the Collatz-Fibonacci numbers, A174429. By Tony's
> formula from 2010, I get a(3) = 21. But by the formula in the title, I get
> a(3) = 60. Maybe I've made some simple mistake of arithmetic or logic. Can
> someone take a look to see if they don't or if they also see an
> inconsistency?

For me the formula in the title agrees with the given terms, including 
a(3) = 21. I used the following Sage code.

def collatz(n) :
     if n%2==0 : return n//2
     return 3*n+1

def a(n) :
     if n==1 or n==2 : return 1
     return a(collatz(n)) + a(collatz(collatz(n)))

I get the same results from Tony's formula.

-- 
Eric Schmidt