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 1-3 of 3 results.

A067070 Cubes whose product of digits is a cube > 0.

Original entry on oeis.org

1, 8, 24389, 226981, 9393931, 11239424, 17373979, 36264691, 66923416, 94818816, 348913664, 435519512, 463684824, 549353259, 555412248, 743677416, 3929352552, 4982686912, 5526456832, 11329982936, 12374478297, 12681938368, 15142552424
Offset: 1

Views

Author

Amarnath Murthy, Jan 05 2002

Keywords

Examples

			24389 is in the sequence because (1) it is a cube and (2) the product of its digits is 2*4*3*8*9, = 1728 which is a cube > 0.
		

References

  • Felice Russo, A set of new Smarandache Functions, Sequences and conjectures in number theory, American Research Press, Lupton USA.

Crossrefs

Intersection of A237767 and A000578.

Programs

  • Mathematica
    pdcQ[n_]:=Module[{pd=Times@@IntegerDigits[n]},pd>0&&IntegerQ[ Surd[ pd,3]]]; Select[Range[3000]^3,pdcQ] (* Harvey P. Dale, Jun 01 2015 *)
  • PARI
    isA237767(k)={my(p=vecprod(digits(k))); p && ispower(p,3)}
    { for (m=1, 2500, if(isA237767(m^3), print1(m^3, ", "))) } \\ Harry J. Smith, May 04 2010
    
  • PARI
    first(n) = {
         my(res = List(), c, vp, i);
         for(i = 1, oo,
              c = i^3;
              vp = vecprod(digits(c));
              if(vp && ispower(vp,3),
                   listput(res, c);
                   if(#res >= n,
                        return(Vec(res))
                   )
              )
         )
    } \\ David A. Corneth, Dec 01 2023

Formula

a(n) = A067071(n)^3. - Andrew Howroyd, Dec 05 2024

Extensions

More terms from Sascha Kurz, Mar 23 2002
One further term from Luc Stevens (lms022(AT)yahoo.com), May 03 2006
Edited by R. J. Mathar, Aug 08 2008
Offset changed from 0 to 1 by Harry J. Smith, May 04 2010

A321881 Numbers whose sum and product of digits are cubes.

Original entry on oeis.org

0, 1, 8, 10, 80, 100, 107, 170, 206, 260, 305, 350, 404, 440, 503, 530, 602, 620, 701, 710, 800, 999, 1000, 1007, 1016, 1025, 1034, 1043, 1052, 1061, 1070, 1106, 1124, 1142, 1160, 1205, 1214, 1241, 1250, 1304, 1340, 1403, 1412, 1421, 1430, 1502, 1520, 1601, 1610, 1700
Offset: 1

Views

Author

Enrique Navarrete, Nov 20 2018

Keywords

Comments

The first numbers in the sequence that are cubes themselves are 0,1,8,1000,8000.
a(22)=999 is the only term up to n=120 related to the cube 27 (the previous ones relate to 0,1,8).
Also, a(22)=999 is the first term that has more than one digit and consists of a single repeated digit; the next ones are 11111111 and 333333333.

Examples

			93111111111111111 (15 ones) is in the sequence since the sum and the product of the digits is 27 (a cube).
333 is not in the sequence since the product of the digits is 27 but the sum is 9 (not a cube).
		

Crossrefs

Programs

  • Magma
    [n:n in [0..2000]| IsPower((&+Intseq(n)), 3) and IsPower((&*Intseq(n)), 3)] // Marius A. Burtea, Jan 21 2019
  • Maple
    filter:= proc(n) local L;
      L:= convert(n,base,10);
      simplify(convert(L,`+`)^(1/3))::integer and
      simplify(convert(L,`*`)^(1/3))::integer;
    end proc:
    select(filter, [$0..1000]); # Robert Israel, Jan 21 2019
  • Mathematica
    cubeQ[n_] := IntegerQ[Surd[n, 3]]; aQ[n_] := cubeQ[Plus @@ IntegerDigits[n]] &&
    cubeQ[Times @@ IntegerDigits[n]]; Select[Range[0, 3000], aQ] (* Amiram Eldar, Nov 20 2018 *)
  • PARI
    isok(n) = my(d=digits(n)); ispower(vecsum(d), 3) && ispower(vecprod(d), 3); \\ Michel Marcus, Nov 29 2018
    

A385056 Prime numbers whose digit product is a positive cube.

Original entry on oeis.org

11, 139, 181, 193, 241, 389, 421, 811, 839, 881, 983, 1181, 1193, 1319, 1777, 1811, 1913, 1931, 1999, 2141, 2221, 2269, 2411, 2663, 3119, 3191, 3313, 3331, 3463, 3643, 3833, 3889, 3911, 4211, 4363, 4441, 4691, 6229, 6263, 6343, 6491, 6661, 7177, 7717, 7877, 8111
Offset: 1

Views

Author

Mohd Anwar Jamal Faiz, Jun 16 2025

Keywords

Crossrefs

Intersection of A000040 and A237767.
Subsequence of A038618.
Cf. A184328.

Programs

  • Maple
    q:= n-> isprime(n) and (p-> p>0 and iroot(p, 3)^3=p)(mul(i, i=convert(n, base, 10))):
    select(q, [$2..10000])[];  # Alois P. Heinz, Jun 16 2025
  • Mathematica
    q[n_] := Module[{pd = Times @@ IntegerDigits[n]}, pd > 0 && IntegerQ[Surd[pd, 3]]]; Select[Prime[Range[1300]], q] (* Amiram Eldar, Jun 16 2025 *)
  • PARI
    isok(k) = if (isprime(k), my(p=vecprod(digits(k))); p && ispower(p, 3)); \\ Michel Marcus, Jun 16 2025
  • Python
    from sympy import primerange, integer_nthroot
    from math import prod
    is_cube = lambda n: n > 0 and integer_nthroot(n, 3)[1]
    digit_product = lambda n: prod(map(int, str(n)))
    cubigit_primes = [p for p in primerange(2, 100000) if is_cube(dp := digit_product(p))]
    print(cubigit_primes)
    
Showing 1-3 of 3 results.