A069147 Numbers k such that tau_3(k) (the number of ordered factorizations of k as k = r*s*t) divides k.

1, 3, 18, 36, 270, 360, 405, 540, 810, 1000, 1620, 1701, 1800, 1890, 2835, 2970, 3000, 3402, 3510, 3780, 4032, 4050, 4455, 4590, 5130, 5265, 5400, 5670, 5940, 6210, 6804, 6885, 7020, 7695, 7830, 8100, 8370, 8505, 8910, 9000, 9180, 9315, 9990, 10260

Offset

1,2

Links

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

Formula

k such that A007425(k) divides k.

Mathematica

f[p_, e_] := (e + 1)*(e + 2)/2; tau3[1] = 1; tau3[n_] := Times @@ f @@@ FactorInteger[n]; Select[Range[10^4], Divisible[#, tau3[#]] &] (* Amiram Eldar, May 17 2020 *)

Prog

(PARI) for(n=1, 15000, if(n%sumdiv(n, d, numdiv(d))==0, print1(n, ", ")))

Crossrefs

Cf. A007425, A033950.

Sequence in context: A372707 A097989 A039700 * A337921 A365442 A094159

Adjacent sequences: A069144 A069145 A069146 * A069148 A069149 A069150

Keyword

easy,nonn

Author

Benoit Cloitre, Apr 08 2002

Status

approved