A354725 - OEIS

%I #7 Jun 05 2022 08:27:31

%S 1,3,25,39,1075,2875,93025,548125,1716775,60231365,9509852725,

%T 111429831875

%N Terms of A354724 whose number of divisors sets a new record.

%C The corresponding numbers of divisors are 1, 2, 3, 4, 6, 8, 9, 10, 12, 16, 18, 20, ...

%C a(13) > 1.5*10^11, if it exists.

%t bw[n_] := DigitCount[n, 2, 1]; q[n_] := Module[{d = Divisors[n]}, Union[bw /@ d] == Range[Length[d]]]; seq = {}; dm = 0; Do[If[(d = DivisorSigma[0, n]) > dm && q[n], dm = d; AppendTo[seq, n]], {n, 1, 10^5, 2}]; seq

%Y Cf. A000005, A000120, A354723, A354724.

%K nonn,base,more

%O 1,2

%A _Amiram Eldar_, Jun 04 2022