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A245644
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Numbers n such that n^3 is an arithmetic number.
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2
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1, 3, 5, 7, 11, 13, 14, 15, 17, 19, 21, 23, 24, 29, 31, 33, 35, 37, 39, 41, 42, 43, 46, 47, 51, 52, 53, 55, 56, 57, 59, 61, 62, 65, 66, 67, 69, 70, 71, 73, 77, 79, 80, 83, 85, 87, 89, 91, 93, 94, 95, 97, 101, 103, 105, 107, 109, 111, 113, 114, 115, 117, 119, 120, 123, 127, 129, 131, 133, 137, 138, 139
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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MAPLE
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isArithPow := proc(n, e)
local dvs, d ;
dvs := numtheory[divisors](n^e) ;
add(d, d=dvs)/nops(dvs) ;
if type(%, 'integer') then
true;
else
false;
end if;
end proc:
for n to 300 do
if isArithPow(n, 3) then
printf("%d, ", n) ;
end if;
end do:
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MATHEMATICA
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PROG
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(Haskell)
a245644 n = a245644_list !! (n-1)
a245644_list = filter ((== 1) . a245656 . (^ 3)) [1..]
(Python) from sympy import divisors, divisor_count
[n for n in range(1, 10**3) if not sum(divisors(n**3)) % divisor_count(n**3)] # Chai Wah Wu, Aug 04 2014
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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