A172420 Numbers k that have measure of smoothness J larger than 5, where J = log(k)/log(rad(k)) and rad(k) is the product of the distinct prime divisors of k (A007947).

64, 128, 256, 512, 729, 1024, 2048, 2187, 4096, 6561, 8192, 8748, 9216, 10368, 11664, 12288, 13122, 13824, 15552, 15625, 16384, 17496, 18432, 19683, 20736, 23328, 24576, 26244, 27648, 31104, 32768, 34992, 36864, 39366, 41472, 46656, 49152

Offset

1,1

Comments

This sequence is a subsequence of A049094, A172418, and A172419.

Links

Amiram Eldar, Table of n, a(n) for n = 1..3000 (terms 1..368 from Harvey P. Dale)

Mathematica

aa = {}; Do[kk = FactorInteger[c]; nn = 1; Do[nn = nn*kk[[n]][[1]], {n, 1, Length[kk]}]; If[Log[c]/Log[nn] > 5, AppendTo[aa, c]], {c, 2, 10000}]; aa
Select[Range[2, 50000], Log[Times@@FactorInteger[#][[All, 1]], #]>5&] (* Harvey P. Dale, Apr 30 2018 *)

Crossrefs

Cf. A007947, A049094, A059172, A172418, A172419, A172421, A172422.

Sequence in context: A031489 A043335 A023708 * A069493 A076470 A256820

Adjacent sequences: A172417 A172418 A172419 * A172421 A172422 A172423

Keyword

nonn

Author

Artur Jasinski, Feb 02 2010

Status

approved