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 1-4 of 4 results.

A185550 Numbers not of the form ceiling(n^(3/2)); complement of A185549.

Original entry on oeis.org

2, 4, 5, 7, 9, 10, 11, 13, 14, 16, 17, 18, 20, 21, 22, 24, 25, 26, 28, 29, 30, 31, 33, 34, 35, 36, 38, 39, 40, 41, 43, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 72, 73, 74, 75, 76, 78, 79, 80, 81, 82, 84, 85, 86, 87, 88, 89, 91, 92, 93, 94, 95, 96, 98, 99, 100, 101, 102, 103, 105, 106, 107, 108, 109, 110, 112, 113, 114, 115, 116, 117, 119, 120, 121, 122, 123, 124, 126, 127, 128, 129, 130, 131, 132, 134, 135, 136, 137, 138, 139, 140, 142, 143, 144, 145, 146, 147, 148, 150
Offset: 1

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Author

Clark Kimberling, Jan 30 2011

Keywords

Crossrefs

Programs

  • Haskell
    import Data.List.Ordered (minus)
    a185550 n = a185550_list !! (n-1)
    a185550_list = [0..] `minus` a185549_list
    -- Reinhard Zumkeller, Jul 24 2015
    
  • Mathematica
    f[n_]=Ceiling[n^(3/2)];
    t1=Table[f[n],{n,1,90}];t1  (* A185549 *)
    t2=Complement[Range[150], Table[f[n],{n,1,80}]];t2  (* A185550 *)
  • Python
    from sympy import integer_nthroot
    def A185550(n):
        def f(x): return n+integer_nthroot(x**2,3)[0]
        def iterfun(f,n=0):
            m, k = n, f(n)
            while m != k: m, k = k, f(k)
            return m
        return iterfun(f,n) # Chai Wah Wu, Sep 09 2024

A000093 a(n) = floor(n^(3/2)).

Original entry on oeis.org

0, 1, 2, 5, 8, 11, 14, 18, 22, 27, 31, 36, 41, 46, 52, 58, 64, 70, 76, 82, 89, 96, 103, 110, 117, 125, 132, 140, 148, 156, 164, 172, 181, 189, 198, 207, 216, 225, 234, 243, 252, 262, 272, 281, 291, 301, 311, 322, 332, 343, 353, 364, 374, 385, 396, 407, 419, 430
Offset: 0

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Author

Keywords

References

  • B. K. Agarwala and F. C. Auluck, Statistical mechanics and partitions into non-integral powers of integers, Proc. Camb. Phil. Soc., 47 (1951), 207-216.
  • 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

Integer part of square root of n^k: A000196 (k=1), this sequence (k=3), A155013 (k=5), A155014 (k=7), A155015 (k=11), A155016 (k=13), A155018 (k=15), A155019 (k=17).
Cf. A002821.
Cf. A185549.

Programs

  • Haskell
    a000093 = a000196 . a000578  -- Reinhard Zumkeller, Jul 11 2014
    
  • Maple
    Digits := 100: A000093 := n->floor(evalf(n^(3/2)));
  • Mathematica
    Table[ Floor[ Sqrt[n^3]], {n, 0, 60}]
  • PARI
    a(n)=if(n<0,0,sqrtint(n^3))
    
  • Python
    from math import isqrt
    def A000093(n): return isqrt(n**3) # Chai Wah Wu, Sep 08 2024

Formula

a(n) = A077121(n) - 1. [Reinhard Zumkeller, Oct 31 2009]
a(n) = floor(n*sqrt(n)). [Arkadiusz Wesolowski, Jun 01 2011]
a(n) = A000196(A000578(n)) = A074704(n)+n*A000196(n). [Reinhard Zumkeller, Jun 27 2011]

Extensions

More terms from James Sellers, May 04 2000

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

A144968 Number of squares between consecutive cubes.

Original entry on oeis.org

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

Views

Author

Reinhard Zumkeller, Sep 27 2008, Sep 29 2008

Keywords

Comments

a(n) = sum {A010052(k): n^3 <= k < (n+1)^3}. - Reinhard Zumkeller, Jul 24 2015, corrected.

Crossrefs

Programs

  • Haskell
    a144968 n = a144968_list !! n
    a144968_list = zipWith (-) (tail a185549_list) a185549_list
    -- Reinhard Zumkeller, Jul 24 2015
    
  • Mathematica
    Last[#]-First[#]&/@Partition[Table[Ceiling[n^(3/2)],{n,0,90}],2,1] (* Harvey P. Dale, Jul 10 2013 *)
  • PARI
    for(n=0,50, print1(ceil((n+1)^(3/2)) - ceil(n^(3/2)), ", ")) \\ G. C. Greubel, Jul 08 2017

Formula

a(n) = ceiling((n+1)^(3/2)) - ceiling(n^(3/2)).
Showing 1-4 of 4 results.