Ruud H.G. van Tol on Sun, 20 Nov 2022 11:22:47 +0100


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Re: A306044(n)




On 2022-11-17 02:10, Ruud H.G. van Tol wrote:
On 2022-11-16 23:39, Ruud H.G. van Tol wrote:
Revised code:
Cleaned it up a bit further:

{
A306044(n, f= primes(3))=
my(q= sum(k=1, #f, 1/log(f[k])));
for
( i= 1, #f
, my( p= logint(exp(n/q), f[i]), d=0, j=0, m=0);
  while
  ( j < n
  , m= f[i]^(p+d);
    j= 1 + sum(k=1, #f, logint(m, f[k]));
    if(j==n, return(m));
    d++
  )
);
error("huh?")

/*
- Best if /f/ is an ordered set of coprimes.
- Observation: with f = primes(P), d <= logint(P, 2).
*/
}

Example run:

? [ a306044(n,[3,4]) |n<-[1..15] ]
[1, 3, 4, 9, 16, 27, 64, 81, 243, 256, 729, 1024, 2187, 4096, 6561]


-- Ruud