NB. prime or prime power nearest to y
NB. prime power must be power of x or higher
NB. default for x is 2
pp=: 2&$: : (4 : 0)
c=. ({. + [EMAIL PROTECTED]@(-/)) _4 4 p:"0 y NB. candidate
integers
e=. 2+i._1+<.x^.{:c NB. possible exponents
excluding 1
p=. e <[EMAIL PROTECTED]:/ c NB. possible
prime bases
b=. (1 p:"0 c) +. +./(x<:p)*.(1 p: p)*.c="1 p^e NB. mask for primes & prime
powers
y ((i.<./)@:|@:- { ]) b#c
)
pp 63
64
3 pp 63
61
] n=: 2^100x
1267650600228229401496703205376
pp n
1267650600228229401496703205376
3 pp n
1267650600228229401496703205361
A tacit version of this solution is left as an
exercise for the reader.
----- Original Message -----
From: Roger Hui <[EMAIL PROTECTED]>
Date: Thursday, September 21, 2006 12:31 pm
Subject: Re: [Jprogramming] Explicit to Tacit - newbie question
> j=. _4 4 p:"0 n are the integers that need to be
> considered. If m (here m=.3) is the smallest prime
> whose powers are in the running, then the highest
> possible exponent is <.m^.{:j . The problem is
> manageable.
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