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A358068
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Numbers that share a (decimal) digit with the sum of their proper divisors.
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0
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6, 11, 12, 13, 14, 16, 17, 18, 19, 20, 21, 26, 28, 31, 32, 35, 40, 41, 42, 44, 46, 51, 56, 60, 61, 64, 68, 70, 71, 72, 74, 76, 80, 84, 86, 91, 93, 95, 96, 100, 101, 102, 103, 104, 106, 107, 108, 109, 110, 111, 112, 113, 114, 120, 121, 124, 125, 126, 127, 128, 130, 131, 132, 135, 136
(list;
graph;
refs;
listen;
history;
text;
internal format)
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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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72 is in the sequence since 72 shares a digit with the sum of its proper divisors 123. Both numbers share the digit "2".
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PROG
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(Python)
from itertools import count, islice
from sympy import divisor_sigma
def A358068_gen(startvalue=2): # generator of terms >= startvalue
for n in count(max(startvalue, 2)):
s = set(str(divisor_sigma(n)-n))
if any(d in s for d in set(str(n))):
yield n
(PARI) isok(n) = #setintersect(Set(digits(sigma(n)-n)), Set(digits(n))); \\ Michel Marcus, Oct 30 2022
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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