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A213239
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Numbers n such that sum of digits of n = sum of digits of anti-divisors of n.
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2
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5, 8, 64, 691, 1779, 2851, 6361, 9066, 9606, 9771, 10789, 10996, 18996, 21481, 22569, 27529, 27691, 31516, 36709, 36776, 42649, 48651, 53296, 56586, 58749, 60369, 64794, 72889, 76754, 78766, 79374, 79896, 80989, 86596, 90606, 90879, 92766, 96171, 98979, 108529
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listen;
history;
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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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Sum of digits of 1779 is 1+7+7+9=24.
Anti-divisors of 1779 are 2, 6, 1186 and their digits’ sum is 2+6+1+1+8+6=24.
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MAPLE
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with(numtheory);
local a, b, c, d, k, n;
for n from 1 to q do
a:=0; b:=0;
for k from 2 to n-1 do
if abs((n mod k)-k/2)<1 then
c:=k; while c>0 do b:=b+(c mod 10); c:=trunc(c/10); od; fi; od;
c:=n; d:=0; while c>0 do d:=d+(c mod 10); c:=trunc(c/10); od;
if b=d then print(n); fi; od; end:
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PROG
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(Python)
[n for n in range(1, 10**5) if sum([sum([int(x) for x in str(d)]) for d in range(2, n) if n % d and 2*n % d in [d-1, 0, 1]]) == sum([int(x) for x in str(n)])] # Chai Wah Wu, Aug 08 2014
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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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