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

0,3

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

Links

Table of n, a(n) for n=0..24.

Formula

Other identities:

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

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 *)

Prog

(Scheme, with Antti Karttunen's IntSeq-library)
(define A255409 (RECORD-POS 0 0 A255326))

Crossrefs

Cf. A255326.

Sequence in context: A201880 A022384 A093022 * A363052 A057342 A192195

Adjacent sequences: A255406 A255407 A255408 * A255410 A255411 A255412

Keyword

nonn,more

Author

Antti Karttunen, Mar 23 2015

Extensions

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

Status

approved