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A362853
Numbers with a record number of divisors that are both bi-unitary and exponential.
2
1, 8, 64, 216, 1728, 27000, 46656, 110592, 216000, 2985984, 5832000, 13824000, 74088000, 373248000, 2000376000, 4741632000, 46656000000, 98611128000, 128024064000, 2662500456000, 6311112192000, 16003008000000, 93329542656000, 170400029184000, 5489031744000000
OFFSET
1,2
COMMENTS
Indices of records in A362852.
The first 80 terms are cubes. Are there noncubes in this sequence?
The corresponding record values are 1, 2, 3, 4, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 48, 60, 72, ... (see the link for more values).
MATHEMATICA
f[p_, e_] := DivisorSigma[0, e] - If[OddQ[e], 0, 1]; d[1] = 1; d[n_] := Times @@ f @@@ FactorInteger[n];
v = Cases[Import["https://oeis.org/A025487/b025487.txt", "Table"], {_, _}][[;; , 2]];
seq = {}; dm = 0; Do[If[(dk = d[v[[k]]]) > dm, dm = dk; AppendTo[seq, v[[k]]]], {k, 1, Length[v]}]; seq
CROSSREFS
Cf. A362852.
Subsequence of A025487.
Similar sequences: A293185, A318278.
Sequence in context: A264060 A207250 A208288 * A045825 A208143 A189265
KEYWORD
nonn
AUTHOR
Amiram Eldar, May 05 2023
STATUS
approved