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.

A004164 Sum of digits of n^3.

Original entry on oeis.org

0, 1, 8, 9, 10, 8, 9, 10, 8, 18, 1, 8, 18, 19, 17, 18, 19, 17, 18, 28, 8, 18, 19, 17, 18, 19, 26, 27, 19, 26, 9, 28, 26, 27, 19, 26, 27, 19, 26, 27, 10, 26, 27, 28, 26, 18, 28, 17, 18, 28, 8, 18, 19, 35, 27, 28, 26, 27, 19, 26, 9, 28, 26, 18, 19, 26, 36, 19
Offset: 0

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Author

Keywords

Comments

For the digital root of n^3 see A073636.
The greedy inverse is 1, -1, -1, -1, -1, -1, -1, 2, 3, 4, -1, -1, -1, -1, -1, -1, 14, 9, 13, -1, -1, .. where -1 means the inverse does not exist. Essentially provided by A067177. - R. J. Mathar, Jul 19 2024

Crossrefs

Programs

A067075 a(n) is the smallest number m such that the sum of the digits of m^3 is equal to n^3.

Original entry on oeis.org

0, 1, 2, 27, 1192, 341075, 3848163483, 2064403725539899
Offset: 0

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Author

Amarnath Murthy, Jan 05 2002

Keywords

Comments

If n = 6*k, a(n) <= A002283(n^3/18). For example, a(6) = 3848163483 <= A002283(6^3/18) = 999999999999. - Seiichi Manyama, Aug 12 2017
a(n) >= ceiling(A051885(n^3)^(1/3)). For example a(7) >= ceiling(A051885(7^3)^(1/3)) = ceiling((2*10^38-1)^(1/3)) = 5848035476426 - David A. Corneth, Aug 23 2018
From Zhining Yang, Jun 20 2024: (Start)
a(8) <= 99995999799995999999999.
a(9) <= 999699989999999949999999999999999.
a(10) <= 199999999929999999999949999999999999999999999.
(End)

Examples

			a(3) = 27 as 27^3 = 19683 is the smallest cube whose digit sum = 27 = 3^3.
		

Crossrefs

Cf. A051885, A061912, A067074. Subsequence of A067177.

Programs

  • Mathematica
    Do[k = 1; While[Plus @@ IntegerDigits[k^3] != n^3, k++ ]; Print[k], {n, 1, 6}] (* Ryan Propper, Jul 07 2005 *)
  • PARI
    a(n) = my(k=0); while (sumdigits(k^3) != n^3, k++); k; \\ Seiichi Manyama, Aug 12 2017

Extensions

Corrected and extended by Ryan Propper, Jul 07 2005
a(0)=0 prepended by Seiichi Manyama, Aug 12 2017
a(7) from Zhining Yang, Jun 20 2024

A061096 Let k = n-th number that is a possible digit-sum for a cube (A054966); sequence gives smallest cube with digit-sum k.

Original entry on oeis.org

1, 8, 27, 64, 2744, 729, 2197, 17576, 19683, 6859, 148877, 287496, 438976, 778688, 2299968, 3869893, 43986977, 75686967, 174676879, 596947688, 796597983, 1693669888, 9649992689, 56888939736, 7598896696, 78898389569, 197747699976, 677298787768, 1778597976896
Offset: 0

Views

Author

Amarnath Murthy, Apr 19 2001

Keywords

Examples

			a(5) = 2744, sum of digits = 17, the fifth term of A054966 (1,8,9,10,17,18...)
		

References

  • Amarnath Murthy, Fabricating a perfect cube with a given valid digit sum (to be published)

Crossrefs

Formula

a(n) = A067177(n)^3. - R. J. Mathar, Aug 23 2018

Extensions

More terms from Sascha Kurz, Jan 28 2003
Showing 1-3 of 3 results.