A094020 Least k <= n such that n*bigomega(k) = k*bigomega(n), where bigomega(n) = the number of prime divisors of n (counted with multiplicity) A001222.

1, 2, 3, 2, 5, 3, 7, 8, 9, 5, 11, 12, 13, 7, 15, 12, 17, 18, 19, 20, 21, 11, 23, 18, 25, 13, 27, 28, 29, 30, 31, 32, 33, 17, 35, 27, 37, 19, 39, 30, 41, 42, 43, 44, 45, 23, 47, 48, 49, 50, 51, 52, 53, 54, 55, 42, 57, 29, 59, 45, 61, 31, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

lk[n_]:=Module[{k=1}, While[n PrimeOmega[k]!=k PrimeOmega[n], k++]; k]; Array[lk, 80] (* Harvey P. Dale, Jul 18 2024 *)
seq[lim_] := Module[{s = Table[PrimeOmega[n]/n, {n, 1, lim}], t = Table[0, {lim}]}, Do[t[[i]] = FirstPosition[s, s[[i]]][[1]], {i, 1, lim}]; t] ; seq[100] (* Amiram Eldar, Oct 05 2024 *)

Crossrefs

Cf. A001222, A095305 for k such that a(k) < k.

Sequence in context: A336268 A075105 A265675 * A165609 A358462 A141465

Adjacent sequences: A094017 A094018 A094019 * A094021 A094022 A094023

Keyword

easy,nonn

Author

Jason Earls, May 31 2004

Status

approved