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A352379
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Numbers k such that no nonzero digit of 2*k divides 2*k.
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3
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17, 19, 23, 27, 28, 29, 34, 37, 38, 39, 43, 47, 49, 154, 167, 169, 173, 178, 179, 185, 187, 188, 190, 193, 194, 197, 199, 203, 215, 217, 223, 227, 229, 233, 235, 237, 239, 245, 247, 249, 253, 254, 268, 269, 277, 278, 279, 283, 289, 293, 294, 298, 299, 317, 319, 323, 328, 329, 334, 335, 337, 338, 343
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OFFSET
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1,1
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LINKS
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EXAMPLE
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a(1) = 17 and 2*17 = 34 is not divisible by 3 or 4;
a(2) = 19 and 2*19 = 38 is not divisible by 3 or 8;
a(3) = 23 and 2*23 = 46 is not divisible by 4 or 6;
a(4) = 27 and 2*27 = 54 is not divisible by 5 or 4; etc.
31 is not in the sequence as 2*31 = 62 is divisible by 2.
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MATHEMATICA
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q[n_] := AllTrue[IntegerDigits[2*n], # == 0 || !Divisible[2*n, #] &]; Select[Range[350], q] (* Amiram Eldar, Mar 14 2022 *)
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PROG
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(Python)
def ok(n): return not any(2*n%int(d)==0 for d in set(str(2*n)) if d!='0')
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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STATUS
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approved
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