A255409 - OEIS

%I #14 Mar 04 2024 01:38:19

%S 0,1,4,18,24,27,160,1470,1500,1701,1920,2205,25515,27951,392392,

%T 424710,429000,481250,500500,8824530,8825856,185435250,194922000,

%U 204289085,214451328

%N a(n) = the least k for which A255326(k) = n; positions of records in A255326.

%C Upper bounds of a(25), ..., a(39) are 5144855625, 5167255808, 5418041805, 5449966080, 6041677950, 187630152192, 187692817422, 188598924800, 195087679875, 6235115927040, 6235116982094, 6827777110000, 7028593647075, 7229398816640, 7251520647683, respectively. - _Hiroaki Yamanouchi_, Mar 30 2015

%F Other identities:

%F For all n >= 0, A255326(a(n)) = n.

%t f[0] = 0; f[n_] := f[n] = 1 + f[n - Times @@ FactorInteger[n][[;; , 1]]]; seq[nmax_] := Module[{s = {}, f1, fm = -1}, Do[f1 = f[n]; If[f1 > fm, fm = f1; AppendTo[s, n]], {n, 0, nmax}]; s]; seq[510000] (* _Amiram Eldar_, Mar 04 2024 *)

%o (Scheme, with _Antti Karttunen_'s IntSeq-library)

%o (define A255409 (RECORD-POS 0 0 A255326))

%Y Cf. A255326.

%K nonn,more

%O 0,3

%A _Antti Karttunen_, Mar 23 2015

%E a(14)-a(24) from _Hiroaki Yamanouchi_, Mar 30 2015