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 1-5 of 5 results.

A075847 Difference between n^2 and the largest cube <= n^2.

Original entry on oeis.org

0, 0, 3, 1, 8, 17, 9, 22, 0, 17, 36, 57, 19, 44, 71, 9, 40, 73, 108, 18, 57, 98, 141, 17, 64, 113, 164, 0, 55, 112, 171, 232, 24, 89, 156, 225, 296, 38, 113, 190, 269, 350, 36, 121, 208, 297, 388, 12, 107, 204, 303, 404, 507, 65, 172, 281, 392, 505, 620, 106, 225, 346
Offset: 0

Views

Author

Zak Seidov and Reinhard Zumkeller, Oct 15 2002

Keywords

Comments

a(n) = n^2 - A077106(n).
a(n) = 0 iff n = m^(6*k).
a(n) = 0 when n is a cube. See A070923.

Examples

			a(4)=8 because 4^2 - 2^3 = 8; a(9)=17 because 9^2 - 4^3 = 17.
A077106(20) = 343 = 7^3 is the largest cube <= 20^2 = 400, therefore a(20) = 400 - 343 = 57.
		

Crossrefs

Programs

Extensions

Edited by N. J. A. Sloane at the suggestion of Zak Seidov, Oct 30 2008

A100196 Number of positive integer cubes <= n^2.

Original entry on oeis.org

0, 1, 1, 2, 2, 2, 3, 3, 4, 4, 4, 4, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 18, 18, 18
Offset: 0

Views

Author

Giovanni Teofilatto, Dec 27 2004

Keywords

Crossrefs

Programs

Formula

a(n) = floor(n^(2/3)). - Charles R Greathouse IV, Mar 21 2012
From Amiram Eldar, Apr 05 2025: (Start)
a(n) = A077113(n) - 1.
a(n) = A077106(n)^(1/3). (End)

Extensions

Corrected and extended by Ray Chandler, Jan 09 2005
a(0)=0 inserted by Sean A. Irvine, Jun 22 2020

A077110 Nearest integer cube to n^2.

Original entry on oeis.org

0, 1, 1, 8, 8, 27, 27, 64, 64, 64, 125, 125, 125, 125, 216, 216, 216, 343, 343, 343, 343, 512, 512, 512, 512, 729, 729, 729, 729, 729, 1000, 1000, 1000, 1000, 1000, 1331, 1331, 1331, 1331, 1331, 1728, 1728, 1728, 1728, 1728, 2197, 2197, 2197
Offset: 0

Views

Author

Reinhard Zumkeller, Oct 29 2002

Keywords

Examples

			a(10) = 125, as 125 = 5^3 is the nearest cube to 100 = 10^2.
		

Crossrefs

Cf. A002760 (Squares and cubes). - Zak Seidov, Oct 08 2015

Programs

  • Mathematica
    nic[n_]:=Module[{n2=n^2,s3,c1,c2},s3=Surd[n2,3];c1=Floor[s3]^3;c2= Ceiling[ s3]^3;If[n2-c1Harvey P. Dale, Jul 05 2015 *)
  • Python
    from sympy import integer_nthroot
    def A077110(n):
        n2 = n**2
        a = integer_nthroot(n2,3)[0]
        a2, a3 = a**3, (a+1)**3
        return a3 if a3+a2-2*n2 < 0 else a2 # Chai Wah Wu, Sep 24 2021

Formula

a(n) = if A075847(n) < A070923(n) then A077106(n) else A077107(n).

A077107 Least integer cube >= n^2.

Original entry on oeis.org

0, 1, 8, 27, 27, 27, 64, 64, 64, 125, 125, 125, 216, 216, 216, 343, 343, 343, 343, 512, 512, 512, 512, 729, 729, 729, 729, 729, 1000, 1000, 1000, 1000, 1331, 1331, 1331, 1331, 1331, 1728, 1728, 1728, 1728, 1728, 2197, 2197, 2197, 2197, 2197, 2744
Offset: 0

Views

Author

Reinhard Zumkeller, Oct 29 2002

Keywords

Examples

			a(20) = 512, as 512 = 8^3 is the least cube >= 400 = 20^2.
		

Crossrefs

Programs

  • Mathematica
    Table[Ceiling[Surd[n^2,3]]^3,{n,0,50}] (* Harvey P. Dale, Jan 02 2020 *)

Formula

a(n) - A070923(n) = n^2.
a(n) = A121536(n)^3. - Amiram Eldar, May 17 2025
a(n) = A048763(n^2). - Michel Marcus, May 17 2025

A077113 Number of nonnegative integer cubes <= n^2.

Original entry on oeis.org

1, 2, 2, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 19
Offset: 0

Views

Author

Reinhard Zumkeller, Oct 29 2002

Keywords

Comments

a(n) is the least number m such that m^3 > n^2. - Zak Seidov, May 03 2005

Examples

			Cubes <= 10^2: 0, 1, 8, 27 and 64, hence a(10) = 5.
		

Crossrefs

Programs

  • Mathematica
    Table[Floor[n^(2/3) + 1], {n, 0, 100}] (* Zak Seidov, May 03 2005 *)
  • Python
    from sympy import integer_nthroot
    def A077113(n): return integer_nthroot(n**2,3)[0]+1 # Chai Wah Wu, Aug 15 2025

Formula

a(n) = floor(n^(2/3))+1.
a(n) = [x^(n^2)] (1/(1 - x))*Sum_{k>=0} x^(k^3). - Ilya Gutkovskiy, Apr 20 2018
a(n) = A100196(n) + 1. - Amiram Eldar, Apr 05 2025

Extensions

Edited by N. J. A. Sloane, Aug 29 2008 at the suggestion of R. J. Mathar
Showing 1-5 of 5 results.