A098121 Harshad numbers that are also perfect powers.

1, 4, 8, 9, 27, 36, 81, 100, 144, 216, 225, 243, 324, 400, 441, 512, 576, 900, 1000, 1296, 1521, 1728, 1764, 2025, 2304, 2401, 2601, 2704, 2916, 3600, 3969, 4225, 4356, 4624, 4913, 5184, 5832, 6084, 6400, 7056, 7744, 7776, 8000, 8100, 9216, 10000, 10404

Offset

1,2

Links

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

Example

1296 is a term because 6^4 = 1296 and 1+2+9+6 = 18 and 1296/18 = 72.

Mathematica

Select[Range[10^4], Divisible[#, Plus @@ IntegerDigits[#]] && (# == 1 || GCD @@ FactorInteger[#][[;; , 2]] > 1) &] (* Amiram Eldar, Jan 27 2021 *)

Crossrefs

Intersection of A001597 and A005349.

Sequence in context: A114377 A115697 A075783 * A115656 A076705 A306916

Adjacent sequences: A098118 A098119 A098120 * A098122 A098123 A098124

Keyword

base,easy,nonn

Author

Jason Earls, Sep 24 2004

Status

approved