A255409 a(n) = the least k for which A255326(k) = n; positions of records in A255326.

0, 1, 4, 18, 24, 27, 160, 1470, 1500, 1701, 1920, 2205, 25515, 27951, 392392, 424710, 429000, 481250, 500500, 8824530, 8825856, 185435250, 194922000, 204289085, 214451328

Offset: 0

Author

Antti Karttunen, Mar 23 2015

Keywords

• nonn
• more

Comments

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

Crossrefs

Cf. A255326.

Programs

Mathematica

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 *)

Formula

Other identities:

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

Extensions

a(14)-a(24) from Hiroaki Yamanouchi, Mar 30 2015