A062182 Harmonic mean of digits is 4.

4, 36, 44, 63, 288, 346, 364, 436, 444, 463, 634, 643, 828, 882, 2488, 2666, 2848, 2884, 3366, 3446, 3464, 3636, 3644, 3663, 4288, 4346, 4364, 4436, 4444, 4463, 4634, 4643, 4828, 4882, 6266, 6336, 6344, 6363, 6434, 6443, 6626, 6633, 6662, 8248, 8284

Offset: 1

Author

Vladeta Jovovic, Jun 12 2001

Keywords

• base
• easy
• nonn

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A062179-A062185, A061383-A061388, A061423-A061425.

Programs

Maple

filter:= proc(n) local L;
  L:= convert(n,base,10);
  if has(L,0) then return false fi;
  nops(L)/add(1/i,i=L)=4
end proc:
select(filter, [$1..10^4]); # Robert Israel, Aug 20 2018

Mathematica

Do[ h = IntegerDigits[n]; If[ Sort[h][[1]] != 0 && Length[h]/Apply[Plus, 1/h] == 4, Print[n]], {n, 1, 10^5}]
hm4Q[n_]:=DigitCount[n,10,0]==0&&HarmonicMean[IntegerDigits[n]]==4; Select[Range[9000],hm4Q]  (* Harvey P. Dale, Mar 23 2011 *)

Extensions

More terms from Henry Bottomley, Jul 25 2001