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 1-4 of 4 results.

A237525 Numbers k such that the sum of digits of k^3 is a cube.

Original entry on oeis.org

0, 1, 2, 5, 8, 10, 11, 20, 27, 33, 36, 39, 42, 50, 54, 57, 69, 72, 75, 78, 80, 84, 87, 93, 100, 101, 105, 108, 110, 111, 114, 135, 138, 147, 162, 165, 168, 174, 177, 200, 219, 222, 225, 228, 231, 234, 258, 267, 270, 273, 276, 285, 291, 294, 312
Offset: 1

Views

Author

Derek Orr, Feb 09 2014

Keywords

Comments

If k is in the sequence then so is 10*k. - David A. Corneth, May 26 2021

Examples

			36^3 = 46656. DigitSum(46656) = 27 (also a cube). So, 36 is a member of this sequence.
		

Crossrefs

Programs

  • PARI
    isok(n) = ispower(sumdigits(n^3), 3); \\ Michel Marcus, Feb 09 2014

Formula

a(n) = A053058(n)^(1/3).

A371004 Fourth powers whose digital sum is also a fourth power.

Original entry on oeis.org

0, 1, 10000, 14641, 100000000, 104060401, 146410000, 1000000000000, 1004006004001, 1040604010000, 1464100000000, 4228599998736, 8670998958336, 9748688599521, 9948826238976, 12598637895936, 19226786746896, 19896452775936, 20699669996721, 23768199069696, 26599197668481
Offset: 1

Views

Author

Stefano Spezia, Mar 08 2024

Keywords

Comments

Among the terms of this sequence, there are:
the numbers of the form 10^(4*k) with k >= 0;
the numbers of the form (10^i + 10^j)^4 with i > j >= 0.

Crossrefs

Programs

  • Mathematica
    Select[Range[0,2500]^4, IntegerQ[DigitSum[#]^(1/4)]&]

Formula

a(n) = A371047(n)^4.

A180738 Largest n-digit cube whose sum of digits is also a cube, or 0 if there is no such number.

Original entry on oeis.org

8, 0, 512, 8000, 74088, 804357, 8000000, 74088000, 804357000, 9474296896, 99832769119, 999100269973, 9970304382667, 99910262316808, 999100269973000, 9981565340125231, 99912200160380167, 999100269973000000
Offset: 1

Views

Author

Daniel Mondot, Oct 08 2010

Keywords

Crossrefs

Programs

  • Mathematica
    Join[{8,0},Table[Module[{c=Floor[Surd[10^n-1,3]]^3},While[!IntegerQ[ Surd[Total[IntegerDigits[c]],3]],c=(Surd[c,3]-1)^3];c],{n,3,20}]] (* Harvey P. Dale, May 28 2015 *)

Extensions

Corrected by Arkadiusz Wesolowski at the suggestion of T. D. Noe, Jun 08 2011

A236077 Cubes which remain (integer) cubes when divided by their digital sum.

Original entry on oeis.org

1, 8, 512, 1000, 8000, 19683, 35937, 46656, 59319, 74088, 125000, 157464, 185193, 328509, 373248, 421875, 474552, 512000, 592704, 658503, 804357, 1000000, 1157625, 1259712, 1331000, 1367631, 1481544, 2460375, 2628072
Offset: 1

Views

Author

K. D. Bajpai, Jan 19 2014

Keywords

Examples

			19683 is in the sequence because 19683 divided by its digital sum (1+9+6+8+3 = 27) gives 729 which is also a cube: 729 = 9^3.
46656 is in the sequence because 46656 divided by its digital sum (4+6+6+5+6 = 27) gives 1728 which is also a cube: 1728 = 12^3.
		

Crossrefs

Intersection of A005349 and A053058.
Cf. A000578 (cubes), A007953 (digital sum).

Programs

  • Maple
    with(StringTools):KD := proc() local a,b,d,e; a:=n^3; b:=add( i,i = convert((a), base, 10))(a); d:=a/b; e:=evalf(d^(1/3));  if e=floor(e) then RETURN (a); fi;  end: seq(KD(), n=1..200);
  • PARI
    digsum(n) = d=eval(Vec(Str(n))); sum(i=1, #d, d[i])
    s=[]; for(n=1, 200, d=digsum(n^3); if(n^3%d==0 && ispower(n^3\d, 3), s=concat(s, n^3))); s \\ Colin Barker, Jan 22 2014
Showing 1-4 of 4 results.