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A046841
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Sum of divisors divides sum of cubes of divisors.
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3
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1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 24, 26, 27, 29, 30, 31, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 46, 47, 48, 51, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85
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listen;
history;
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internal format)
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OFFSET
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1,2
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LINKS
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Paolo P. Lava, Table of n, a(n) for n = 1..1000
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EXAMPLE
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x=208. The power sums of divisors for k=0,1,2,3 are as follows: 10,434,54970,10288838; sigma(1,208)=434 divides sigma(4,208)= 234*23707.
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MAPLE
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with(numtheory);
List046841:=proc(q) local a, b, k, n;
for n from 1 to q do
a:=divisors(n); b:=add(a[k]^3, k=1..nops(a));
if type(b/sigma(n), integer) then print(n); fi;
od; end:
List046841(10^6); # Paolo P. Lava, Apr 10 2013
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MATHEMATICA
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Select[Range@ 85, Divisible[DivisorSigma[3, #], DivisorSigma[1, #]] &] (* Michael De Vlieger, Aug 01 2017 *)
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PROG
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(PARI) isA046841(n)=sigma(n, 3)%sigma(n, 1)==0 \\ Michael B. Porter, Apr 07 2010
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CROSSREFS
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Cf. A000203, A001158.
Cf. A003601, A020486.
Sequence in context: A175084 A171519 A072099 * A244218 A164514 A000037
Adjacent sequences: A046838 A046839 A046840 * A046842 A046843 A046844
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KEYWORD
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nonn
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AUTHOR
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Labos Elemer
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STATUS
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approved
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