On Tue, May 24, 2016 at 09:12:43AM -0400, Charles Greathouse wrote:
> Yes, but if you don't have a special formula and all you have is a string,
> that doesn't help.

Well, you can do:
s=Str(10^10^7);N=fromdigits(apply(x->x-48,Vec(Vecsmall(s))));

My point was that the fast algorithm is already implemented,
but that the parser does not use it for historical reason.

> Note: this was discussed on the Mersenne forum, starting here:
> http://www.mersenneforum.org/showthread.php?p=434341#post434341

Can you reproduce the problem with writebin ?

Cheers,
Bill.