OFFSET
1,1
COMMENTS
FORMULA
a(n) ~ n.
EXAMPLE
18 is in sequence because the list of divisors of 18: (1, 2, 3, 6, 9, 18) contains digit 9.
MATHEMATICA
Select[Range@108, Part[Plus @@ DigitCount@ Divisors@ #, 9] > 0 &] (* after Michael De Vlieger *)
PROG
(Magma) [n: n in [1..1000] | [9] subset Setseq(Set(Sort(&cat[Intseq(d): d in Divisors(n)])))]
(PARI) is(n)=fordiv(n, d, if(setsearch(Set(digits(d)), 9), return(1))); 0 \\ after Charles R Greathouse IV
(Python)
from itertools import count, islice
from sympy import divisors
def A257226_gen(): return filter(lambda n:any('9' in str(d) for d in divisors(n, generator=True)), count(1))
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, May 29 2015
STATUS
approved