Re: 2^[1,3]

["Ruud H.G. van Tol" <rvtol@isolution.nl>]

On 2025-01-29 14:42, Bill Allombert wrote:
> On Wed, Jan 29, 2025 at 02:28:46PM +0100, Ruud H.G. van Tol wrote:

>> ? vecsum(2^[1,3])
>> % 10.000000000000000000000000000000000000
>
> Use fromdigits:
> ? fromdigits([1,3],2)
> % = 10

Doesn't work:

? fromdigits([1,3],2)
% = 5
(because 1*2^1 + 3*2^0 = 2+3 = 5)


The (distinct) digits are exponents, are not positional.
2^1 + 2^3 = 10.


Example quest:

>> How to best convert something like (int) 6131786 to (int) 2^1 + 2^3 
+ 2^6 +
>> 2^7 + 2^8?
>
> You can use the binary() function.

I don't see yet how.

-- Ruud