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 1-8 of 8 results.

A077119 a(n) = A077118(n) - n^3.

Original entry on oeis.org

0, 0, 1, -2, 0, -4, 9, 18, 17, 0, 24, -35, 36, 12, -40, -11, 0, -13, -56, 30, -79, -45, -39, -67, 100, 0, 113, -83, -48, -53, -104, 138, -7, 163, -100, -26, 0, -28, -116, 217, 9, 248, -104, 17, 80, 79, 8, -139, 297, 0, 316, -155, 17, 119, 145, 89, -55
Offset: 0

Views

Author

Reinhard Zumkeller, Oct 29 2002

Keywords

Comments

a(n)=0 iff n = m^(6*k).
Values d=x^3-y^2 of extremal points of elliptic Mordell curves. Definition for extremal points see A200656. Each value x has only one value of distance d when coordinate x is extremal point, but for many fixed distances d, the elliptic curve has more than 1 extremal point. - Artur Jasinski, Nov 30 2011
Theorem (Artur Jasinski): If a(n)>0 then a(n)<(4n^(3/2)-1)/4 for every n. If a(n)<0 then a(n)>(-4n^(3/2)-1)/4 for every n. a(n)=0 then n is perfect square. - Artur Jasinski, Dec 08 2011

Examples

			A077118(10)=1024=32^2 is the nearest square to 10^3=1000, therefore a(10)=1024-1000=24.
		

Crossrefs

|a(n)| = A002938(n).

Programs

  • Magma
    [Round(Sqrt(n^3))^2-n^3: n in [0..60]]; // Vincenzo Librandi, Mar 24 2015
    
  • Maple
    A077119 := proc(n)
        (round( sqrt(n^3) ))^2-n^3 ;
    end proc: # R. J. Mathar, Jan 18 2021
  • Mathematica
    Table[Round[Sqrt[x^3]]^2 - x^3, {x, 0, 100}]  (* Artur Jasinski, Nov 30 2011 *)
  • Python
    from math import isqrt
    def A077119(n): return ((m:=isqrt(k:=n**3))+int((k-m*(m+1)<<2)>=1))**2-k # Chai Wah Wu, Jul 29 2022

Formula

a(n) = if A077116(n) < A070929(n) then -A077116(n) else A070929(n).

A077116 n^3 - A065733(n).

Original entry on oeis.org

0, 0, 4, 2, 0, 4, 20, 19, 28, 0, 39, 35, 47, 81, 40, 11, 0, 13, 56, 135, 79, 45, 39, 67, 135, 0, 152, 83, 48, 53, 104, 207, 7, 216, 100, 26, 0, 28, 116, 270, 496, 277, 104, 546, 503, 524, 615, 139, 368, 0, 391, 155, 732, 652, 648, 726, 55, 293, 631, 170, 704
Offset: 0

Views

Author

Reinhard Zumkeller, Oct 29 2002

Keywords

Comments

a(n) = 0 for n = m^2. - Zak Seidov, May 11 2007
It has been asked whether some primes do not occur in this sequence. It seems indeed that primes 3, 5, 17, 23, 29, 31, 37, 41, 43, 59, 61,... do not occur, primes 2, 7, 11, 13, 19, 47, 53, 67, 79, 83,... do. For further investigations, see A087285 = the range of this sequence, and also the related sequences A229618 = range of A181138, and A165288. - M. F. Hasler, Sep 26 2013 and Oct 05 2013

Examples

			A065733(10) = 961 = 31^2 is the largest square less than or equal to 10^3 = 1000, therefore a(10) = 1000 - 961 = 39.
		

Crossrefs

Programs

Formula

a(n) = A154333(n) unless n is a square or, equivalently, a(n)=0. - M. F. Hasler, Oct 05 2013
a(n) = A053186(n^3). - R. J. Mathar, Jul 12 2016

A065733 Largest square <= n^3.

Original entry on oeis.org

0, 1, 4, 25, 64, 121, 196, 324, 484, 729, 961, 1296, 1681, 2116, 2704, 3364, 4096, 4900, 5776, 6724, 7921, 9216, 10609, 12100, 13689, 15625, 17424, 19600, 21904, 24336, 26896, 29584, 32761, 35721, 39204, 42849, 46656, 50625, 54756, 59049, 63504
Offset: 0

Views

Author

Labos Elemer, Nov 15 2001

Keywords

Examples

			a(10) = 961, as 961 = 31^2 is the largest square <= 1000 = 10^3.
		

Crossrefs

Programs

  • Haskell
    a065733 n = head [x | x <- reverse [0.. n^3], a010052 x == 1] -- Reinhard Zumkeller, Oct 10 2013
  • Mathematica
    Table[Floor[Sqrt[w^3]//N]^2, {w, 1, 50}]
  • PARI
    A065733(n)=sqrtint(n^3)^2  \\ M. F. Hasler, Oct 05 2013
    

Formula

a(n) + A077116(n) = n^3.
a(n) = A048760(n^3).
n^3 - 2*n^(3/2) <= a(n) <= n^3. - Charles R Greathouse IV, Dec 05 2022
a(n) = A000093(n)^2. - Amiram Eldar, Jul 14 2024

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).

A002821 a(n) = nearest integer to n^(3/2).

Original entry on oeis.org

0, 1, 3, 5, 8, 11, 15, 19, 23, 27, 32, 36, 42, 47, 52, 58, 64, 70, 76, 83, 89, 96, 103, 110, 118, 125, 133, 140, 148, 156, 164, 173, 181, 190, 198, 207, 216, 225, 234, 244, 253, 263, 272, 282, 292, 302, 312, 322, 333, 343, 354, 364, 375, 386, 397
Offset: 0

Views

Author

Keywords

References

  • M. Boll, Tables Numériques Universelles. Dunod, Paris, 1947, p. 46.
  • M. Hall, Jr., The Diophantine equation x^3-y^2=k, pp. 173-198 of A. O. L. Atkin and B. J. Birch, editors, Computers in Number Theory. Academic Press, NY, 1971.
  • A. V. Lebedev and R. M. Fedorova, A Guide to Mathematical Tables. Pergamon, Oxford, 1960, p. 17.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Haskell
    a002821 = round . sqrt . fromIntegral . (^ 3)
    -- Reinhard Zumkeller, Jul 11 2014
    
  • Maple
    A002821 := proc(n)
        round(n^(3/2)) ;
    end proc:
    seq(A002821(n),n=0..100) ;
  • Mathematica
    t[n_]:=Module[{flt=Floor[n],cet=Ceiling[n]},If[n-fltHarvey P. Dale, May 12 2011 *)
  • Python
    from math import isqrt
    def A002821(n): return (m:=isqrt(k:=n**3))+int((k-m*(m+1)<<2)>=1) # Chai Wah Wu, Jul 30 2022

Formula

a(n) = floor(n^(3/2) + 1/2). - Ridouane Oudra, Nov 13 2019
a(n) = sqrt(A077118(n)). - Chai Wah Wu, Jul 30 2022

A070929 Smallest integer >= 0 of the form x^2 - n^3.

Original entry on oeis.org

0, 0, 1, 9, 0, 19, 9, 18, 17, 0, 24, 38, 36, 12, 65, 106, 0, 128, 97, 30, 100, 148, 168, 154, 100, 0, 113, 198, 249, 260, 225, 138, 356, 163, 297, 389, 0, 423, 353, 217, 9, 248, 441, 17, 80, 79, 8, 506, 297, 0, 316, 574, 17, 119, 145, 89, 784, 568, 252, 737, 225, 548
Offset: 0

Views

Author

Benoit Cloitre, May 20 2002

Keywords

Comments

a(n)=0 iff n is a square.

Examples

			A077115(10) = 1024 = 32^2 is the least square >= 10^3 = 1000, therefore a(10) = 1024 - 1000 = 24.
		

Crossrefs

Programs

  • Mathematica
    f[n_]=Ceiling[n^(3/2)]^2-n^3;
    t1=Table[f[n], {n, 1, 90}]; t1 (* Clark Kimberling, Jan 30 2011 *)
  • PARI
    for(n=1,100,print1(ceil(n^(3/2))^2-n^3,","))

Formula

a(n) = ceiling(n^(3/2))^2 - n^3 = A077115(n) - n^3.

A077115 Least integer square >= n^3.

Original entry on oeis.org

0, 1, 9, 36, 64, 144, 225, 361, 529, 729, 1024, 1369, 1764, 2209, 2809, 3481, 4096, 5041, 5929, 6889, 8100, 9409, 10816, 12321, 13924, 15625, 17689, 19881, 22201, 24649, 27225, 29929, 33124, 36100, 39601, 43264, 46656, 51076, 55225, 59536
Offset: 0

Views

Author

Reinhard Zumkeller, Oct 29 2002

Keywords

Examples

			a(10) = 1024, as 1024 = 32^2 is the least square >= 1000 = 10^3.
		

Crossrefs

Programs

  • Magma
    [Ceiling(n^(3/2))^2: n in [0..50]]; // Vincenzo Librandi, Feb 17 2015
  • Mathematica
    lis[n_]:=Module[{c=Sqrt[n^3]},If[IntegerQ[c],c^2,(Floor[c]+1)^2]]; Array[lis,40,0] (* Harvey P. Dale, Jan 22 2013 *)

Formula

a(n) - A070929(n) = n^3.
a(n) = ceiling(n^(3/2))^2. - Benoit Cloitre, Nov 01 2002
a(n) = A185549(n)^2. - Amiram Eldar, May 17 2025
a(n) = A048761(n^3). - Michel Marcus, May 17 2025

A077120 n^3 times nearest integer square to n^3.

Original entry on oeis.org

0, 1, 72, 675, 4096, 15125, 48600, 123823, 270848, 531441, 1024000, 1724976, 3048192, 4853173, 7419776, 11353500, 16777216, 24073700, 33685632, 47251651, 63368000, 85349376, 112964632, 147220700, 192485376, 244140625
Offset: 0

Views

Author

Reinhard Zumkeller, Oct 29 2002

Keywords

Programs

  • Mathematica
    n3ts[n_]:=Module[{n3=n^3,a,b,sr},sr=Sqrt[n3];a=(Floor[sr])^2;b=(Ceiling[ sr])^2;If[n3-aHarvey P. Dale, Nov 27 2011 *)

Formula

a(n) = A000578(n)*A077118(n).
Showing 1-8 of 8 results.