RE : Divisors concatenated shape a prime

[Eric Angelini]

Geee, Simon !
Simple routine but... great result ! Waow !
Thanks to you and everyone -- this list is a must ;-)
Best,
É.
 
 

________________________________

De: Simon Plouffe [mailto:simon.plouffe at gmail.com]
Date: jeu. 19/07/2007 22:54
À: Eric Angelini
Cc: seqfan at ext.jussieu.fr
Objet : Re: Divisors concatenated shape a prime



hello I made
this simple maple routine :
###############################
with(numtheory):

for k from 5 to 1e99 do:
v0:=divisors(k):

nn:=nops(v0):
if nn > 3 then
v1:=[seq(v0[j],j=2..nn-1)]:
v2:=cat(seq(convert(v1[n],string),n=1..nops(v1))):
v3:=parse(v2):
if isprime(v3) = true then lprint(k,v3) fi:
fi:
od:
#################################

and here is some output from it
(see the attachement)
#################################

Simon plouffe


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