cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-7 of 7 results.

A062185 Harmonic mean of digits is 8.

Original entry on oeis.org

8, 88, 888, 6999, 8888, 9699, 9969, 9996, 68999, 69899, 69989, 69998, 86999, 88888, 89699, 89969, 89996, 96899, 96989, 96998, 98699, 98969, 98996, 99689, 99698, 99869, 99896, 99968, 99986, 688999, 689899, 689989, 689998, 698899, 698989
Offset: 1

Views

Author

Vladeta Jovovic, Jun 12 2001

Keywords

Crossrefs

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

Programs

  • Mathematica
    Do[ h = IntegerDigits[n]; If[ Sort[h][[1]] != 0 && Length[h]/Apply[Plus, 1/h] == 8, Print[n]], {n, 1, 10^6}]
Select[Range[700000],DigitCount[#,10,0]==0&&HarmonicMean[IntegerDigits[ #]]==8&] (* Harvey P. Dale, Jan 27 2012 *)

Extensions

More terms from Robert G. Wilson v, Aug 08 2001

A062180 Harmonic mean of digits is 2.

Original entry on oeis.org

2, 22, 136, 144, 163, 222, 316, 361, 414, 441, 613, 631, 1236, 1244, 1263, 1326, 1333, 1362, 1424, 1442, 1623, 1632, 2136, 2144, 2163, 2222, 2316, 2361, 2414, 2441, 2613, 2631, 3126, 3133, 3162, 3216, 3261, 3313, 3331, 3612, 3621, 4124, 4142, 4214, 4241
Offset: 1

Views

Author

Vladeta Jovovic, Jun 12 2001

Keywords

Links

Crossrefs

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

Programs

  • Maple
    h:= proc(L) local m,x,i,t;
  m:= nops(L)+1;
  x:= m/2 - add(1/t, t=L);
  if x > 0 then
    x:= 1/x;
    if x::posint and x <= 9 then
      return(x + add(L[i]*10^i,i=1..m-1))
  fi fi
end proc:
f:= n -> h(map(`+`,convert(n,base,9),1)):
g:= n -> h([op(map(`+`,convert(n,base,9),1)),1]):
R:= 2:
for d from 1 to 4 do
  R:= R, seq(f(i),i=9^(d-1)..9^d-1),seq(g(i),i=9^(d-1)..9^d-1)
od:
R; # Robert Israel, Apr 05 2021
  • Mathematica
    Do[ h = IntegerDigits[n]; If[ Sort[h][[1]] != 0 && Length[h]/Apply[Plus, 1/h] == 2, Print[n]], {n, 1, 10^4}]

Extensions

More terms from Henry Bottomley, Jul 25 2001

A062182 Harmonic mean of digits is 4.

Original entry on oeis.org

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

Views

Author

Vladeta Jovovic, Jun 12 2001

Keywords

Links

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

A062183 Numbers such that harmonic mean of digits is 5.

Original entry on oeis.org

5, 55, 555, 5555, 26999, 28888, 29699, 29969, 29996, 33999, 34688, 34868, 34886, 36488, 36666, 36848, 36884, 38468, 38486, 38648, 38684, 38846, 38864, 39399, 39939, 39993, 43688, 43868, 43886, 44488, 44666, 44848, 44884, 46388, 46466
Offset: 1

Views

Author

Vladeta Jovovic, Jun 12 2001

Keywords

Links

Crossrefs

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

Programs

  • Mathematica
    Do[ h = IntegerDigits[n]; If[ Sort[h][[1]] != 0 && Length[h]/Apply[Plus, 1/h] == 5, Print[n]], {n, 1, 10^6}]
Select[Range[50000],HarmonicMean[IntegerDigits[#]]==5&] (* Harvey P. Dale, Sep 27 2018 *)

Extensions

More terms from Robert G. Wilson v, Aug 08 2001

A061546 Harmonic mean of digits is 7.

Original entry on oeis.org

7, 77, 777, 7777, 77777, 777777, 3999999, 4688999, 4689899, 4689989, 4689998, 4698899, 4698989, 4698998, 4699889, 4699898, 4699988, 4868999, 4869899, 4869989, 4869998, 4886999, 4888888, 4889699, 4889969, 4889996, 4896899
Offset: 1

Views

Author

Vladeta Jovovic, Jun 13 2001

Keywords

Examples

			6666999 is a term since 7/(1/6+1/6+1/6+1/6+1/9+1/9+1/9)=7.

Crossrefs

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

Programs

  • Mathematica
    Do[ h = IntegerDigits[n]; If[ Sort[h][[1]] != 0 && Length[h]/Apply[Plus, 1/h] == 7, Print[n]], {n, 1, 10^6}]

Extensions

More terms from Robert G. Wilson v, Aug 08 2001

A062181 Harmonic mean of digits is 3.

Original entry on oeis.org

3, 26, 33, 62, 236, 244, 263, 326, 333, 362, 424, 442, 623, 632, 1999, 2266, 2336, 2344, 2363, 2434, 2443, 2626, 2633, 2662, 3236, 3244, 3263, 3326, 3333, 3362, 3424, 3442, 3623, 3632, 4234, 4243, 4324, 4342, 4423, 4432, 6226, 6233, 6262, 6323, 6332
Offset: 1

Views

Author

Vladeta Jovovic, Jun 12 2001

Keywords

Links

Crossrefs

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

Programs

  • Mathematica
    Do[ h = IntegerDigits[n]; If[ Sort[h][[1]] != 0 && Length[h]/Apply[Plus, 1/h] == 3, Print[n]], {n, 1, 10^4}]
  • Python
    from fractions import Fraction
def hm(n):
  s = str(n)
  return None if '0' in s else len(s)/sum(Fraction(1, int(d)) for d in s)
def aupto(limit): return [m for m in range(limit+1) if hm(m) == 3]
print(aupto(6332)) # Michael S. Branicky, Mar 26 2021

Extensions

More terms from Henry Bottomley, Jul 25 2001

A062184 Harmonic mean of digits is 6.

Original entry on oeis.org

6, 66, 488, 666, 848, 884, 3999, 4688, 4868, 4886, 6488, 6666, 6848, 6884, 8468, 8486, 8648, 8684, 8846, 8864, 9399, 9939, 9993, 36999, 38888, 39699, 39969, 39996, 44999, 46688, 46868, 46886, 48668, 48686, 48866, 49499, 49949, 49994, 63999
Offset: 1

Views

Author

Vladeta Jovovic, Jun 12 2001

Keywords

Crossrefs

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

Programs

  • Mathematica
    Do[ h = IntegerDigits[n]; If[ Sort[h][[1]] != 0 && Length[h]/Apply[Plus, 1/h] == 6, Print[n]], {n, 1, 10^6}]

Extensions

More terms from Robert G. Wilson v, Aug 08 2001
Showing 1-7 of 7 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.