OFFSET
1,1
COMMENTS
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..71
EXAMPLE
35 = 5*7
333 = 3*3*37
335 = 5*67
445 = 5*89
33445 = 5*6689
333333333333333333333333444444444444444444444445 = 5*66666666666666666666666688888888888888888888889
PROG
(Python)
from itertools import count, islice, combinations_with_replacement
from sympy import isprime, factorint
def A372151_gen(): # generator of terms
for l in count(1):
for d in combinations_with_replacement('345', l):
a, n = d[-1], int(''.join(d))
if not isprime(n):
for p in factorint(n, multiple=True):
s = str(p)
if s[0] < a or sorted(s) != list(s):
break
a = s[-1]
else:
yield n
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Chai Wah Wu, Apr 26 2024
STATUS
approved