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A348273 Noninfinitary superabundant numbers: numbers m such that nisigma(m)/m > nisigma(k)/k for all k < m, where nisigma(m) is the sum of noninfinitary divisors of m (A348271). 2
1, 4, 12, 16, 36, 48, 144, 720, 3600, 25200, 176400, 226800, 1587600, 1940400, 2494800, 17463600, 32432400, 192099600, 227026800, 2497294800, 3632428800, 32464832400, 39956716800 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
The least term k with A348271(k)/k > m for m = 1, 2, 3, .... is 36, 3600, 1587600, ...
LINKS
MATHEMATICA
f[p_, e_] := Module[{b = IntegerDigits[e, 2], m}, m = Length[b]; Product[If[b[[j]] > 0, 1 + p^(2^(m - j)), 1], {j, 1, m}]]; isigma[1] = 1; isigma[n_] := Times @@ f @@@ FactorInteger[n]; s[n_] := DivisorSigma[1, n] - isigma[n]; seq = {}; rm = -1; Do[r1 = s[n]/n; If[r1 > rm, rm = r1; AppendTo[seq, n]], {n, 1, 10^6}]; seq
CROSSREFS
Cf. A348271.
Subsequence of A348272.
The noninfinitary version of A004394.
Similar sequences: A002110 (unitary), A037992 (infinitary), A061742 (exponential), A292984, A329882.
Sequence in context: A273501 A291781 A348342 * A253122 A239413 A351893
KEYWORD
nonn,more
AUTHOR
Amiram Eldar, Oct 09 2021
STATUS
approved

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Last modified July 20 12:45 EDT 2024. Contains 374445 sequences. (Running on oeis4.)