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.

A255494 Triangle read by rows: coefficients of numerator of generating functions for powers of Pell numbers.

Original entry on oeis.org

1, 1, 1, 1, 4, 1, 1, 13, 13, 1, 1, 38, 130, 38, 1, 1, 105, 1106, 1106, 105, 1, 1, 280, 8575, 26544, 8575, 280, 1, 1, 729, 62475, 567203, 567203, 62475, 729, 1, 1, 1866, 435576, 11179686, 32897774, 11179686, 435576, 1866, 1, 1, 4717, 2939208, 207768576, 1736613466, 1736613466, 207768576, 2939208, 4717, 1
Offset: 0

Views

Author

N. J. A. Sloane, Mar 06 2015

Keywords

Comments

Note that Table 8 by Falcon should be labeled with the powers n (not r) and that the labels are off by 1. - R. J. Mathar, Jun 14 2015

Examples

			Triangle begins:
  1;
  1,    1; # see A079291
  1,    4,      1; # see A110272
  1,   13,     13,        1;
  1,   38,    130,       38,        1;
  1,  105,   1106,     1106,      105,        1;
  1,  280,   8575,    26544,     8575,      280,      1;
  1,  729,  62475,   567203,   567203,    62475,    729,    1;
  1, 1866, 435576, 11179686, 32897774, 11179686, 435576, 1866, 1;
		

Crossrefs

Programs

  • Magma
    P:= func< n | Round(((1 + Sqrt(2))^n - (1 - Sqrt(2))^n)/(2*Sqrt(2))) >;
    function T(n,k)
      if k eq 0 or k eq n then return 1;
      else return P(n-k+1)*T(n-1,k-1) + P(k+1)*T(n-1,k);
      end if; return T;
    end function;
    [T(n,k): k in [0..n], n in [0..12]];
    
  • Mathematica
    T[n_, k_]:= T[n,k]= If[k==0 || k==n, 1, Fibonacci[n-k+1, 2]*T[n-1, k-1] + Fibonacci[k+1, 2]*T[n-1, k]]; Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Sep 19 2021 *)
  • Sage
    @CachedFunction
    def P(n): return lucas_number1(n, 2, -1)
    def T(n,k): return 1 if (k==0 or k==n) else P(n-k+1)*T(n-1, k-1) + P(k+1)*T(n-1, k)
    flatten([[T(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Sep 19 2021

Formula

From G. C. Greubel, Sep 19 2021: (Start)
T(n, k) = P(n-k+1)*T(n-1, k-1) + P(k+1)*T(n-1, k), where T(n, 0) = T(n, n) = 1 and P(n) = A000129(n).
T(n, k) = T(n, n-k).
T(n, 1) = A094706(n).
T(n, 2) = A255495(n-2).
T(n, 3) = A255496(n-3).
T(n, 4) = A255497(n-4).
T(n, 5) = A255498(n-5). (End)

A099930 a(n) = Pell(n) * Pell(n-1) * Pell(n-2) / 10.

Original entry on oeis.org

1, 12, 174, 2436, 34307, 482664, 6791772, 95567064, 1344731653, 18921807828, 266250046986, 3746422451772, 52716164405255, 741772724044560, 10437534301224120, 146867252940711408, 2066579075472320521, 29078974309550454492, 409172219409185308518, 5757490046038128779316
Offset: 3

Views

Author

Ralf Stephan, Nov 03 2004

Keywords

Crossrefs

Cf. A000129. Third column of triangle A099927. Cf. A001656, A084175.

Programs

  • Mathematica
    Drop[CoefficientList[Series[x^3/((1+2x-x^2)(1-14x-x^2)),{x,0,20}],x],3] (* or *) LinearRecurrence[{12,30,-12,-1},{1,12,174,2436},20] (* Harvey P. Dale, Feb 26 2012 *)

Formula

G.f.: x^3 / ((1+2*x-x^2)*(1-14*x-x^2)).
a(n) = 12*a(n-1) + 30*a(n-2) - 12*a(n-3) - a(n-4); a(3)=1, a(4)=12, a(5)=174, a(6)=2436. - Harvey P. Dale, Feb 26 2012
From Peter Bala, Mar 30 2015: (Start)
The following remarks assume an offset of 0.
The o.g.f. A(x) = 1/( (1 + 2*x - x^2)*(1 - 14*x - x^2) ). Hence A(x) (mod 4) = 1/(1 + 2*x - x^2)^2 (mod 4). It follows by Theorem 1 of Heninger et al. that sqrt(A(x)) = 1 + 6*x + 69*x^2 + 804*x^3 + ... has integral coefficients.
Sum_{n >= 0} a(n+3)*x^n = exp( Sum_{n >= 1} Pell(4*n)/Pell(n)*x^n/n ). Cf. A001656, A084175. (End)
a(n+1) = (1/2)*Sum_{k=1..n-1} ( A014445(k)*A110272(n-k) ) for n > 1. - Michael A. Allen, Jan 25 2023

A213688 a(n) = Sum_{i=0..n} A000129(i)^3.

Original entry on oeis.org

0, 1, 9, 134, 1862, 26251, 369251, 5196060, 73113372, 1028784997, 14476099149, 203694183170, 2866194639170, 40330419190351, 567492063162119, 7985219303802744, 112360562315573112, 1581033091723823881, 22246823846444284881, 313036566941955454910
Offset: 0

Views

Author

N. J. A. Sloane, Jun 18 2012

Keywords

Crossrefs

Cf. A000129, A048739 (partial sums of A000129), A084158 (sum of squares of A000129).
Cf. A110272 (cubes of the Pell numbers).

Programs

Formula

G.f.: x*(1-4*x-x^2)/((1-x)*(1+2*x-x^2)*(1-14*x-x^2)). [Bruno Berselli, Jun 18 2012]
a(n) = ((3+sqrt(2))*(1+sqrt(2))^(3n+1)+(3-sqrt(2))*(1-sqrt(2))^(3n+1)-21*(-1)^n*((1+sqrt(2))^n+(1-sqrt(2))^n)+32)/224. [Bruno Berselli, Jun 18 2012]

A110273 a(n) = Pell(n)^3 + Pell(n+1)^3.

Original entry on oeis.org

1, 9, 133, 1853, 26117, 367389, 5169809, 72744121, 1023588937, 14402985777, 202665398173, 2851718540021, 40126725007181, 564625868522949, 7944888884612393, 111793070252410993, 1573047872420021137, 22134463284128711769, 311455533850231631029, 4382511937187348260781
Offset: 0

Views

Author

Paul Barry, Jul 18 2005

Keywords

Crossrefs

Programs

  • Magma
    I:=[1,9,133,1853]; [n le 4 select I[n] else 12*Self(n-1) + 30*Self(n-2) - 12*Self(n-3) - Self(n-4): n in [1..31]]; // G. C. Greubel, Sep 17 2021
    
  • Mathematica
    LinearRecurrence[{12,30,-12,-1},{1,9,133,1853},30] (* Harvey P. Dale, Jan 24 2018 *)
    Sum[Fibonacci[Range[0, 30] +j, 2]^3, {j,0,1}] (* G. C. Greubel, Sep 17 2021 *)
  • Sage
    [lucas_number1(n+1, 2, -1)^3 + lucas_number1(n, 2, -1)^3 for n in (0..30)] # G. C. Greubel, Sep 17 2021

Formula

G.f.: (1+x)*(1-4*x-x^2)/((1+2*x-x^2)*(1-14*x-x^2)).
a(n) = 12*a(n-1) + 30*a(n-2) - 12*a(n-3) - a(n-4).
a(n) = ( 3*(-1)^n*A001333(n) + Pell(3*n) + Pell(3*(n+1)) )/8.

A244352 a(n) = Pell(n)^3 - Pell(n)^2, where Pell(n) is the n-th Pell number (A000129).

Original entry on oeis.org

0, 0, 4, 100, 1584, 23548, 338100, 4798248, 67750848, 954701400, 13441659268, 189185124940, 2662308356400, 37463104912660, 527155118240244, 7417689205890000, 104375121328998144, 1468671237346368048, 20665783224031936900, 290789699203441908148
Offset: 0

Views

Author

Colin Barker, Jun 26 2014

Keywords

Examples

			a(3) = Pell(3)^3 - Pell(3)^2 = 5^3 - 5^2 = 100.
		

Crossrefs

Programs

  • Magma
    Pell:= func< n | n eq 0 select 0 else Evaluate(DicksonSecond(n-1,-1),2) >;
    [Pell(n)^3 - Pell(n)^2: n in [0..40]]; // G. C. Greubel, Aug 20 2022
    
  • Mathematica
    CoefficientList[Series[4*x^2*(3*x^3-4*x^2+8*x+1) / ((x+1)*(x^2-6*x+1)*(x^2-2*x-1)*(x^2+14*x-1)), {x, 0, 20}], x] (* Vaclav Kotesovec, Jun 26 2014 *)
  • PARI
    pell(n) = round(((1+sqrt(2))^n-(1-sqrt(2))^n)/(2*sqrt(2)))
    vector(50, n, pell(n-1)^3-pell(n-1)^2)
    
  • SageMath
    def Pell(n): return lucas_number1(n,2,-1)
    [Pell(n)^3 -Pell(n)^2 for n in (0..40)] # G. C. Greubel, Aug 20 2022

Formula

a(n) = A110272(n) - A079291(n).
G.f.: 4*x^2*(1+8*x-4*x^2+3*x^3) / ((1+x)*(1-6*x+x^2)*(1+2*x-x^2)*(1-14*x-x^2)).
a(n) = A045991(A000129(n)). - Michel Marcus, Jun 26 2014
Showing 1-5 of 5 results.