login
A337718
Numbers that can be written as (m + product of digits of m) for some m.
6
0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 23, 24, 26, 28, 29, 30, 32, 34, 35, 38, 40, 41, 42, 44, 45, 46, 47, 50, 54, 55, 56, 58, 60, 62, 65, 66, 67, 68, 70, 74, 75, 78, 80, 81, 85, 86, 88, 89, 90, 92, 94, 95, 98, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109
OFFSET
1,2
COMMENTS
Every integer that contains a digit 0 is a term (A011540).
When R_m with m >= 1 is in A002275, then R_m + 1 is a term (A047855 \ {1}).
Near similar:
-> Not-Colombian (A176995) are numbers that can be written as (m + sum of digits of m) for some m.
-> Bogotá numbers (A336826) are numbers that can be written as (m * product of digits of m) for some m.
LINKS
EXAMPLE
10 = 5 + 5 = 10 + (1*0) and 22 = 16 + (1*6) are terms.
MATHEMATICA
m = 100; Select[Union[Table[n + Times @@ IntegerDigits[n], {n, 0, m}]], # <= m &] (* Amiram Eldar, Sep 16 2020 *)
PROG
(PARI) isok(m) = {if (m==0, return (1)); for (k=1, m, if (k+vecprod(digits(k)) == m, return (1)); ); } \\ Michel Marcus, Sep 17 2020
(Python)
from math import prod
def b(n): return n + prod(map(int, str(n)))
def aupto(n): return sorted(set(b(m) for m in range(n+1) if b(m) <= n))
print(aupto(109)) # Michael S. Branicky, Jan 09 2023
CROSSREFS
Subsequences: A011540, A047855 \ {1}.
Range of A230099.
Cf. A176995 (not Colombian), A336826 (Bogotá numbers).
Sequence in context: A092451 A214673 A055962 * A246410 A195169 A338922
KEYWORD
nonn,base
AUTHOR
Bernard Schott, Sep 16 2020
STATUS
approved