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.

Previous Showing 41-50 of 51 results. Next

A132983 a(n) = ceiling(n^(1/3) + n^(1/4)).

Original entry on oeis.org

2, 3, 3, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8
Offset: 1

Views

Author

Mohammad K. Azarian, Nov 18 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Ceiling[Surd[n,3]+Surd[n,4]],{n,80}] (* Harvey P. Dale, May 07 2014 *)
  • PARI
    for(n=1, 50, print1(ceil(n^(1/3) + n^(1/4)), ", ")) \\ G. C. Greubel, Sep 28 2017

A134919 Floor(n^(5/3)).

Original entry on oeis.org

1, 3, 6, 10, 14, 19, 25, 32, 38, 46, 54, 62, 71, 81, 91, 101, 112, 123, 135, 147, 159, 172, 186, 199, 213, 228, 243, 258, 273, 289, 305, 322, 339, 356, 374, 392, 410, 429, 448, 467, 487, 507, 527, 548, 569, 590, 612, 633, 656
Offset: 1

Views

Author

Mohammad K. Azarian, Nov 17 2007

Keywords

Crossrefs

Programs

A262872 Expansion of (Sum_{i>=0} x^(i^2)) * (Sum_{j>=0} x^(j^3)) / (1-x).

Original entry on oeis.org

1, 3, 4, 4, 5, 6, 6, 6, 7, 9, 10, 10, 11, 11, 11, 11, 12, 14, 14, 14, 14, 14, 14, 14, 15, 16, 17, 18, 19, 19, 19, 20, 20, 21, 21, 21, 23, 24, 24, 24, 24, 24, 24, 25, 26, 26, 26, 26, 26, 27, 28, 28, 29, 29, 29, 29, 29, 30, 30, 30, 30, 30, 30, 31, 32, 33, 33, 33, 34, 34, 34
Offset: 0

Views

Author

Ran Pan, Oct 03 2015

Keywords

Comments

a(n) is number of nonnegative integer solutions (x,y,z) such that x + y^2 + z^3 = n.

Examples

			a(4) = 5 because there are 5 solutions: (5,0,0), (4,1,0), (4,0,1), (3,1,1) and (1,2,0).
		

Crossrefs

Formula

G.f.: (Sum_{i>=0} x^(i^2)) * (Sum_{j>=0} x^(j^3)) / (1-x).

A262874 Expansion of (Sum_{i>=0} x^(i^2)) * (Sum_{j>=0} x^(j^3)) * (Sum_{k>=0} x^(k^4)) / (1-x).

Original entry on oeis.org

1, 4, 7, 8, 9, 11, 12, 12, 13, 16, 19, 20, 21, 22, 22, 22, 24, 29, 32, 32, 33, 34, 34, 34, 36, 40, 43, 45, 48, 49, 49, 50, 52, 55, 56, 56, 58, 61, 62, 62, 63, 64, 65, 67, 70, 71, 71, 72, 72, 74, 76, 77, 80, 82, 82, 82, 82, 83, 84, 85, 86, 86, 86, 87, 89, 92, 94, 94, 96, 97, 97
Offset: 0

Views

Author

Ran Pan, Oct 03 2015

Keywords

Comments

a(n) is number of nonnegative integer solutions (x,x,z,u) such that x + y^2 + z^3 + u^4 = n.

Crossrefs

Formula

G.f.: (Sum_{i>=0} x^(i^2)) * (Sum_{j>=0} x^(j^3)) * (Sum_{k>=0} x^(k^4)) / (1-x).

A342219 a(1) = 1, a(2) = 2; for n > 2, a(n) = the number of terms in the maximal length sum of previous consecutive terms that equals n.

Original entry on oeis.org

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

Views

Author

Scott R. Shannon, Mar 05 2021

Keywords

Comments

The equivalent sequence for a minimal length sum is given by A003059.

Examples

			a(3) = 2 as the only way to sum previous consecutive terms to make 3 is 1 + 2 = 3, which contains two terms.
a(7) = 4 as the previous consecutive terms 1 + 2 + 2 + 2 = 7, which contains four terms. Note that 7 can also be made by consecutive terms 2 + 2 + 3 = 7, but the sequence is the maximal sum length.
a(10) = 5 as the previous consecutive terms 1 + 2 + 2 + 2 + 3 = 10, which contains five terms. Three other consecutive term sums also exist that sum to 10 but they contain fewer terms.
		

Crossrefs

A368941 a(n) = floor(3/2 + sqrt(n)).

Original entry on oeis.org

1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10
Offset: 0

Views

Author

Eric W. Weisstein, Jan 10 2024

Keywords

Comments

Burning number of the n-ladder (for n >= 1), n-Moebius ladder (for n >= 3), and n-prism (for n >= 3) graphs.

Crossrefs

Sequence agrees with the known terms of A155934.

Programs

  • Mathematica
    Table[Floor[3/2 + Sqrt[n]], {n, 50}]
    Floor[3/2 + Sqrt[Range[50]]]
    CoefficientList[Series[(1 + QPochhammer[-x^2, x^4]  QPochhammer[x^8, x^8])/(1 - x), {x, 0, 50}], x]

Formula

a(n) = A000194(n) + 1. - Andrew Howroyd, Jan 10 2024
G.f.: x*(1 + QPochhammer(-x^2, x^4)*QPochhammer(x^8, x^8))/(1 - x).

Extensions

Terms a(26) and beyond from Andrew Howroyd, Jan 10 2024

A123241 Number of squares < lesser of twin primes.

Original entry on oeis.org

2, 3, 4, 5, 6, 7, 8, 9, 11, 11, 12, 13, 14, 14, 15, 16, 16, 17, 17, 18, 19, 21, 21, 22, 23, 24, 25, 25, 26, 26, 29, 29, 29, 30, 30, 32, 33, 33, 33, 34, 34, 36, 36, 36, 37, 37, 38, 39, 39, 39, 41, 41, 41, 42, 42, 43, 44, 44, 44, 45, 45, 46, 46, 46, 46, 47, 47, 48, 48, 49, 49, 49
Offset: 1

Views

Author

Giovanni Teofilatto, Oct 07 2006

Keywords

Crossrefs

Cf. A104103 number of squares < prime(n).

Programs

  • Mathematica
    ltp=Select[Prime[Range[PrimePi[2500]]],PrimeQ[#+2]&];Ceiling[Sqrt[ltp]] (* James C. McMahon, Nov 17 2024 *)

Formula

a(n)=A003059(A001359(n)). - R. J. Mathar, Jun 18 2008

Extensions

More terms from R. J. Mathar, Jun 18 2008

A130819 2*k appears 2*k-1 times.

Original entry on oeis.org

2, 4, 4, 4, 6, 6, 6, 6, 6, 8, 8, 8, 8, 8, 8, 8, 10, 10, 10, 10, 10, 10, 10, 10, 10, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18
Offset: 1

Views

Author

Paul Curtz, Jul 17 2007

Keywords

Comments

The run-length encoding of this sequence is A000027 as it has one 2, three 4's, five 6's, and so on. - Alexander Fraebel, Sep 10 2012

Crossrefs

Equals twice A003059. - Michel Marcus, Sep 14 2020
Cf. A000027.

Formula

Sum_{n>=1} (-1)^(n+1)/a(n) = log(2)/2. - Amiram Eldar, Oct 01 2022

A132913 a(n) = ceiling(sqrt(n) + n^(1/3)).

Original entry on oeis.org

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

Views

Author

Mohammad K. Azarian, Nov 18 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Ceiling[Sqrt[n]+Surd[n,3]],{n,70}] (* Harvey P. Dale, Jul 31 2018 *)

A132914 a(n) = floor(sqrt(n) + n^(1/3)).

Original entry on oeis.org

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

Views

Author

Mohammad K. Azarian, Nov 18 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Floor[Sqrt[n] + n^(1/3)], {n, 100}] (* Wesley Ivan Hurt, Jan 01 2024 *)
Previous Showing 41-50 of 51 results. Next