OFFSET
1,1
COMMENTS
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..10000
EXAMPLE
10201 is a term because the largest digit of all the divisors of 10201 (1, 101, 10201) is 2.
MAPLE
isA221697 := proc(n)
local dgs, d;
dgs := {} ;
for d in numtheory[divisors](n) do
dgs := dgs union convert(convert(d, base, 10), set) ;
end do:
if max(op(dgs)) = 2 then
true;
else
false;
end if;
end proc:
for n from 2 to 112121 do
if isA221697(n) then
printf("%d, ", n) ;
end if;
end do: # R. J. Mathar, Jan 30 2013
MATHEMATICA
Select[Range[115000], Max[Flatten[IntegerDigits/@Divisors[#]]]==2&] (* Harvey P. Dale, Dec 15 2014 *)
PROG
(Python)
from sympy import divisors
def ok(n): return '2' == max("".join(map(str, divisors(n))))
print([m for m in range(1, 112122) if ok(m)]) # Michael S. Branicky, Feb 22 2021
(Python)
from sympy import isprime, divisors
from itertools import count, islice, product
def agen(): # generator of terms
yield 2
for d in count(2):
for f in "12":
for mid in product("012", repeat=d-2):
for e in "12": # ending in zero has 5 as divisor
s = f+"".join(mid)+e
t = int(s)
if "2" in s and isprime(t): yield t; continue
if "2" == max("".join(map(str, divisors(t)))): yield t
print(list(islice(agen(), 50))) # Michael S. Branicky, Aug 03 2022
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Jan 22 2013, corrected Jan 29 2013
STATUS
approved