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## #1 2014-03-03 17:16:14

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 19,939
Website

### Optimising Ackermann Recursions

How can I have a method that calculates Ackermann Functions very fast?

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'You have made another human being happy. There is no greater accomplishment.' -bobbym

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## #2 2014-03-04 05:10:02

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 92,914

### Re: Optimising Ackermann Recursions

Hi;

It would be extremely fast because the numbers grow very large, very quickly, so even with M you could only compute the first few.

For instance:

In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

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## #3 2014-03-04 15:02:03

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 19,939
Website

### Re: Optimising Ackermann Recursions

Suppose I am interested in the last 4 digits of A(4,4)?

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'You have made another human being happy. There is no greater accomplishment.' -bobbym

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## #4 2014-03-04 16:13:50

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,889

### Re: Optimising Ackermann Recursions

Then I'd either find a very fast and powerful computer or do a lot of number theory.

Here lies the reader who will never open this book. He is forever dead.
Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

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## #5 2014-03-04 16:14:52

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 92,914

### Re: Optimising Ackermann Recursions

You can probably get the last 4 digits.

In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

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