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A254572
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Least multiple of n that is abundant or perfect (A023196).
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3
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6, 6, 6, 12, 20, 6, 28, 24, 18, 20, 66, 12, 78, 28, 30, 48, 102, 18, 114, 20, 42, 66, 138, 24, 100, 78, 54, 28, 174, 30, 186, 96, 66, 102, 70, 36, 222, 114, 78, 40, 246, 42, 258, 88, 90, 138, 282, 48, 196, 100, 102, 104, 318, 54, 220, 56, 114, 174, 354, 60
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OFFSET
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1,1
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COMMENTS
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See A254571(n) = a(n)/n for the multipliers.
Very often a(n) = A064162(n), but the definition of the latter requires strict abundance.
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LINKS
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Robert Israel, Table of n, a(n) for n = 1..10000
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MAPLE
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f:= proc(n) local k; uses numtheory;
for k from 1 to 4 do if sigma(k*n)>=2*k*n then return k*n fi od:
6*n
end proc:
map(f, [$1..100]); # Robert Israel, Feb 10 2019
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MATHEMATICA
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a[n_] := Do[If[DivisorSigma[1, k*n] >= 2*k*n, Return[k*n]], {k, {1, 2, 3, 4, 6}}];
Table[a[n], {n, 1, 100}] (* Jean-François Alcover, Feb 09 2023 *)
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PROG
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(PARI) a(n) = forstep(m=n, 6*n, n, if(sigma(m)>=2*m, return(m)))
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CROSSREFS
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Cf. A023196, A064162, A254571.
Sequence in context: A315828 A315829 A180604 * A360561 A109047 A337814
Adjacent sequences: A254569 A254570 A254571 * A254573 A254574 A254575
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KEYWORD
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nonn
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AUTHOR
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Jeppe Stig Nielsen, Feb 01 2015
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STATUS
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approved
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