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.

A278937 Numbers k such that 3 is the largest decimal digit of k^3.

Original entry on oeis.org

11, 101, 110, 1001, 1010, 1100, 10001, 10010, 10100, 11000, 100001, 100010, 100100, 101000, 110000, 684917, 1000001, 1000010, 1000100, 1001000, 1010000, 1100000, 6849170, 10000001, 10000010, 10000100, 10001000, 10010000, 10100000, 11000000
Offset: 1

Views

Author

Colin Barker, Dec 02 2016

Keywords

Comments

A038444 is a subsequence. Are there an infinite number of terms not in A038444 that are not a multiple of 10? - Chai Wah Wu, Dec 02 2016
Conjecture: sequence is equal to A038444 plus terms of the form 684917*10^k for k >= 0. - Chai Wah Wu, Sep 02 2017
Conjecture is true up to 4.8*10^18. - Giovanni Resta, Sep 03 2017

Examples

			684917 is in the sequence because 684917^3 = 321302302131323213.

Links

Crossrefs

Cf. A000578 (the cubes: n^3), A038444, A277960 (analog for squares), A278936 (cubes of the terms: a(n)^3).
Cf. A031997 (the odd terms).

Programs

  • Magma
    [n: n in [1..2*10^7] | Max(Intseq(n^3)) eq 3]; // Vincenzo Librandi, Dec 03 2016
  • Mathematica
    Select[Range[11 10^6],Max[IntegerDigits[#^3]]==3&] (* Harvey P. Dale, Feb 11 2025 *)
  • PARI
    select(n->vecmax(digits(n^3))==3, vector(1000000, n, n))

Formula

a(n)^3 = A278936(n).

A052004 Numbers k such that k^3 has only even digits.

Original entry on oeis.org

0, 2, 4, 20, 40, 200, 202, 400, 1822, 1824, 1902, 2000, 2002, 2020, 4000, 4352, 18220, 18240, 19020, 20000, 20002, 20020, 20200, 34372, 39154, 40000, 43520, 182200, 182400, 190200, 200000, 200002, 200020, 200200, 202000, 297092, 343720, 391540
Offset: 1

Views

Author

Patrick De Geest, Nov 15 1999

Keywords

Links

Crossrefs

Cf. A000578, A034376, A030099, A030100, A030479, A030483, A031997, A076165, A076166, A076171, A137468.

Programs

  • Mathematica
    Select[ Range[ 500000 ], Union[ EvenQ[ IntegerDigits[ #^3 ] ] ] == {True} & ]
Select[Range[0,400000],AllTrue[IntegerDigits[#^3],EvenQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Oct 15 2017 *)

A061809 When cubed gives number composed just of the digits 1, 2, 3, 4.

Original entry on oeis.org

1, 7, 11, 68, 1039247
Offset: 1

Views

Author

Robert G. Wilson v, Jun 23 2001

Keywords

Comments

No more terms through 10^13. - Jon E. Schoenfield, Jul 03 2010
No more terms through 5*10^16. - David A. Corneth, Mar 17 2019

Crossrefs

Cf. A031997 (odd and digits 0,1,2,3), A043681 (0,1,2,3), A048792 (0,1,2,3,4), A061813 (1,2,3,4,5).

Programs

  • Mathematica
    Do[ If[ Union[ Join[ {1, 2, 3, 4}, IntegerDigits[n^3] ]] == {1, 2, 3, 4}, Print[n]], {n, 0, 10^8} ]
Table[Surd[#,3]&/@Select[FromDigits/@Tuples[{1,2,3,4},n],IntegerQ[ Surd[ #,3]]&],{n,6}]//Flatten (* The program generates the first 4 terms of the sequence; to generate the 5th term, change the "6" to "19," but the program will take a long time to run. *) (* Harvey P. Dale, Apr 13 2021 *)
Showing 1-3 of 3 results.

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

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