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A345387
Numbers k such that k, 2k, 3k, 4k all contain digit 1.
0
531, 541, 1053, 1054, 2571, 3051, 3061, 3071, 3105, 3106, 3107, 3157, 3551, 3561, 3571, 3581, 3591, 4051, 4061, 4071, 4081, 4091, 4105, 4106, 4107, 4108, 4109, 4155, 4156, 4157, 4158, 4159, 4551, 4561, 4571, 4581, 4591, 5031, 5041, 5103, 5104, 5128, 5129, 5153, 5154
OFFSET
1,1
EXAMPLE
The first four multiples of 531 are 531, 1062, 1593, and 2124. All of them contain digit 1.
MATHEMATICA
Select[Range[10000], Length[ Position[IntegerDigits[#], 1]] > 0 && Length[ Position[IntegerDigits[2 #], 1]] > 0 && Length[ Position[IntegerDigits[3 #], 1]] > 0 && Length[ Position[IntegerDigits[4 #], 1]] > 0 &]
PROG
(Python)
def ok(n): return all('1' in str(k*n) for k in [1, 2, 3, 4])
print(list(filter(ok, range(5155)))) # Michael S. Branicky, Jun 17 2021
CROSSREFS
Cf. A011531.
Sequence in context: A098259 A174761 A031967 * A031521 A156772 A031701
KEYWORD
nonn,base
AUTHOR
Tanya Khovanova, Jun 17 2021
STATUS
approved