OFFSET
1,1
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..10000
EXAMPLE
c(1) = 1 not prime -> 1 is not a term.
c(2) = 2 prime -> 2 is a term.
c(3) = 3 prime -> 3 is a term.
c(4) = 22 not prime -> 4 is not a term.
c(5) = 5 prime -> 5 is a term.
c(6) = 23 prime -> 6 is a term.
MAPLE
q:= n-> isprime(parse(cat(sort(map(i-> i[1]$i[2], ifactors(n)[2]))[]))):
select(q, [$2..222])[]; # Alois P. Heinz, Mar 27 2024
MATHEMATICA
m[{p_, e_}] := Table[p, {e}]; c[w_] := FromDigits[Join @@ IntegerDigits@ w]; Select[ Range@ 150, PrimeQ@ c@ Flatten[m /@ FactorInteger[#]] &] (* Giovanni Resta, Apr 23 2021 *)
PROG
(Python)
from sympy import *
def b(n):
f=factorint(n)
l=sorted(f)
return 1 if n==1 else int("".join(str(i)*f[i] for i in l))
# print([b(n) for n in range(1, 101)])
for n in range(1, 200):
if isprime(b(n)):
print (n)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Wim JA Bruyninckx, Apr 02 2021
STATUS
approved