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 11-16 of 16 results.

A094444 Triangular array T(n,k) = Fibonacci(n+4-k)*C(n,k), k=0..n, n>=0.

Original entry on oeis.org

3, 5, 3, 8, 10, 3, 13, 24, 15, 3, 21, 52, 48, 20, 3, 34, 105, 130, 80, 25, 3, 55, 204, 315, 260, 120, 30, 3, 89, 385, 714, 735, 455, 168, 35, 3, 144, 712, 1540, 1904, 1470, 728, 224, 40, 3, 233, 1296, 3204, 4620, 4284, 2646, 1092, 288, 45, 3, 377, 2330, 6480, 10680, 11550, 8568, 4410, 1560, 360, 50, 3
Offset: 0

Views

Author

Clark Kimberling, May 03 2004

Keywords

Comments

Row sums are Fibonacci numbers.
Row sums with alternating signs are Fibonacci numbers or their negatives.

Examples

			First few rows:
   3;
   5,   3;
   8,  10,   3;
  13,  24,  15,  3;
  21,  52,  48, 20,  3;
  34, 105, 130, 80, 25, 3;
		

Crossrefs

Programs

  • GAP
    Flat(List([0..12], n-> List([0..n], k-> Binomial(n,k)*Fibonacci(n-k+4) ))); # G. C. Greubel, Oct 30 2019
  • Magma
    [Binomial(n,k)*Fibonacci(n-k+4): k in [0..n], n in [0..12]]; // G. C. Greubel, Oct 30 2019
    
  • Maple
    with(combinat); seq(seq(fibonacci(n-k+4)*binomial(n,k), k=0..n), n=0..12); # G. C. Greubel, Oct 30 2019
  • Mathematica
    Table[Fibonacci[n-k+4]*Binomial[n,k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Oct 30 2019 *)
  • PARI
    T(n,k) = binomial(n,k)*fibonacci(n-k+4);
    for(n=0,12, for(k=0,n, print1(T(n,k), ", "))) \\ G. C. Greubel, Oct 30 2019
    
  • Sage
    [[binomial(n,k)*fibonacci(n-k+4) for k in (0..n)] for n in (0..12)] # G. C. Greubel, Oct 30 2019
    

Formula

From G. C. Greubel, Oct 30 2019: (Start)
T(n,k) = binomial(n,k)*Fibonacci(n-k+4).
Sum_{k=0..n} T(n,k) = Fibonacci(2*n+4).
Sum_{k=0..n} (-1)^(k+1) * T(n,k) = (-1)^n * Fibonacci(n-4). (End)

A081569 Fourth binomial transform of F(n+1).

Original entry on oeis.org

1, 5, 26, 139, 757, 4172, 23165, 129217, 722818, 4050239, 22718609, 127512940, 715962889, 4020920141, 22584986378, 126867394723, 712691811325, 4003745802188, 22492567804517, 126361939999081, 709898671705906, 3988211185370615, 22405825905923321, 125876420631268204
Offset: 0

Views

Author

Paul Barry, Mar 22 2003

Keywords

Comments

Binomial transform of A081568.
Case k = 4 of family of recurrences a(n) = (2*k+1)*a(n-1) - A028387(k-1)*a(n-2) for n >= 2, with a(0) = 1 and a(1) = k + 1.
a(n) = 5^n * a(n;1/5) = Sum_{k=0..n} binomial(n,k) * (-1)^k * F(k-1) * 5^(n-k), which implies also Deléham's formula given below and where a(n;d), n=0,1,...,d, denote the delta-Fibonacci numbers defined in comments to A000045 (see also Witula's et al. papers). - Roman Witula, Jul 12 2012

Crossrefs

Programs

  • GAP
    a:=[1,5];; for n in [3..30] do a[n]:=9*a[n-1]-19*a[n-2]; od; a; # G. C. Greubel, Aug 12 2019
  • Magma
    I:=[1, 5]; [n le 2 select I[n] else 9*Self(n-1)-19*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Aug 09 2013
    
  • Maple
    seq(coeff(series((1-4*x)/(1-9*x+19*x^2), x, n+1), x, n), n = 0 .. 30); # G. C. Greubel, Aug 12 2019
  • Mathematica
    CoefficientList[Series[(1-4x)/(1 -9x +19x^2), {x, 0, 30}], x] (* Vincenzo Librandi, Aug 09 2013 *)
  • PARI
    Vec((1-4*x)/(1-9*x+19*x^2) + O(x^30)) \\ Altug Alkan, Dec 10 2015
    
  • Sage
    def A081569_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P((1-4*x)/(1-9*x+19*x^2)).list()
    A081569_list(30) # G. C. Greubel, Aug 12 2019
    

Formula

a(n) = 9*a(n-1) - 19*a(n-2) for n >= 2, with a(0) = 1 and a(1) = 5.
a(n) = (1/2 - sqrt(5)/10)*(9/2 - sqrt(5)/2)^n + (sqrt(5)/10 + 1/2)*(sqrt(5)/2 + 9/2)^n.
G.f.: (1 - 4*x)/(1 - 9*x + 19*x^2).
a(n) = Sum_{k=0..n} A094441(n,k)*4^k. - Philippe Deléham, Dec 14 2009
a(n) = A081574(n) - 4*A081574(n-1). - R. J. Mathar, Jul 19 2012
E.g.f.: exp(9*x/2)*(5*cosh(sqrt(5)*x/2) + sqrt(5)*sinh(sqrt(5)*x/2))/5. - Stefano Spezia, Jun 03 2024

A081568 Third binomial transform of Fibonacci(n+1).

Original entry on oeis.org

1, 4, 17, 75, 338, 1541, 7069, 32532, 149965, 691903, 3193706, 14745009, 68084297, 314394980, 1451837593, 6704518371, 30961415074, 142980203437, 660285858245, 3049218769908, 14081386948661, 65028302171639, 300302858766202, 1386808687475385, 6404329365899473
Offset: 0

Views

Author

Paul Barry, Mar 22 2003

Keywords

Comments

Binomial transform of A081567.
Case k=3 of family of recurrences a(n) = (2k+1)*a(n-1) - A028387(k-1)*a(n-2) for n >= 2, with a(0) = 1 and a(1) = k + 1.
a(n) = 4^n*a(n;1/4) = Sum_{k=0..n} binomial(n,k) * (-1)^k * F(k-1) * 4^(n-k), which also implies Deléham's formula given below and where a(n;d), n = 0, 1, ..., d, denote the delta-Fibonacci numbers defined in comments to A000045 (see also Witula's et al. papers). - Roman Witula, Jul 12 2012

Crossrefs

Cf. A000045, A161731 (INVERT transform), A007582 (INVERTi transform), A028387, A081567, A081569 (binomial transform), A094441, A099453.

Programs

  • GAP
    a:=[1,4];; for n in [3..30] do a[n]:=7*a[n-1]-11*a[n-2]; od; a; # G. C. Greubel, Aug 12 2019
  • Magma
    I:=[1, 4]; [n le 2 select I[n] else 7*Self(n-1)-11*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Aug 09 2013
    
  • Maple
    seq(coeff(series((1-3*x)/(1-7*x+11*x^2), x, n+1), x, n), n = 0 .. 30); # G. C. Greubel, Aug 12 2019
  • Mathematica
    CoefficientList[Series[(1-3x)/(1 -7x +11x^2), {x, 0, 30}], x] (* Vincenzo Librandi, Aug 09 2013 *)
    LinearRecurrence[{7,-11},{1,4},30] (* Harvey P. Dale, Feb 01 2015 *)
  • PARI
    Vec((1-3*x)/(1-7*x+11*x^2) + O(x^30)) \\ Altug Alkan, Dec 10 2015
    
  • Sage
    def A081568_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P((1-3*x)/(1-7*x+11*x^2)).list()
    A081568_list(30) # G. C. Greubel, Aug 12 2019
    

Formula

a(n) = 7*a(n-1) - 11*a(n-2) for n >= 2, with a(0) = 1 and a(1) = 4.
a(n) = (1/2 - sqrt(5)/10)*(7/2 - sqrt(5)/2)^n + (sqrt(5)/10 + 1/2)*(sqrt(5)/2 + 7/2)^n = A099453(n) - 3*A099453(n-1).
G.f.: (1 - 3*x)/(1 - 7*x + 11*x^2).
a(n) = Sum_{k=0..n} A094441(n,k)*3^k. - Philippe Deléham, Dec 14 2009
G.f.: Q(0,u)/x - 1/x, where u = x/(1 - 3*x), Q(k,u) = 1 + u^2 + (k+2)*u - u*(k + 1 + u)/Q(k+1); (continued fraction). - Sergei N. Gladkovskii, Oct 07 2013
E.g.f.: exp(7*x/2)*(5*cosh(sqrt(5)*x/2) + sqrt(5)*sinh(sqrt(5)*x/2))/5. - Stefano Spezia, Jun 03 2024

A081570 Fifth binomial transform of F(n+1).

Original entry on oeis.org

1, 6, 37, 233, 1490, 9633, 62753, 410926, 2700349, 17786985, 117346714, 774991289, 5121849473, 33865596822, 223987930325, 1481764925737, 9803764203682, 64870223394129, 429263295428641, 2840659771285310, 18798621916707821
Offset: 0

Views

Author

Paul Barry, Mar 22 2003

Keywords

Comments

Binomial transform of A081569.
Case k=5 of family of recurrences a(n) = (2k+1)*a(n-1) - A028387(k-1)*a(n-2), a(0)=1, a(1)=k+1.

Crossrefs

Cf. A000045.

Programs

  • GAP
    a:=[1,6];; for n in [3..30] do a[n]:=11*a[n-1]-29*a[n-2]; od; a; # G. C. Greubel, Aug 12 2019
  • Magma
    I:=[1, 6]; [n le 2 select I[n] else 11*Self(n-1)-29*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Aug 09 2013
    
  • Maple
    seq(coeff(series((1-5*x)/(1-11*x+29*x^2), x, n+1), x, n), n = 0 .. 30); # G. C. Greubel, Aug 12 2019
  • Mathematica
    CoefficientList[Series[(1-5x)/(1 -11x +29x^2), {x, 0, 30}], x] (* Vincenzo Librandi, Aug 09 2013 *)
    LinearRecurrence[{11,-29},{1,6},30] (* Harvey P. Dale, Aug 04 2022 *)
  • PARI
    my(x='x+O('x^30)); Vec((1-5*x)/(1-11*x+29*x^2)) \\ G. C. Greubel, Aug 12 2019
    
  • Sage
    def A081570_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P((1-5*x)/(1-11*x+29*x^2)).list()
    A081570_list(30) # G. C. Greubel, Aug 12 2019
    

Formula

a(n) = 11*a(n-1) - 29*a(n-2), a(0)=1, a(1)=6.
a(n) = (1/2 - sqrt(5)/10)*(11/2 - sqrt(5)/2)^n + (sqrt(5)/10 + 1/2)*(sqrt(5)/2 + 11/2)^n .
G.f.: (1-5*x)/(1-11*x+29*x^2).
a(n) = Sum_{k=0..n} A094441(n,k)*5^k. - Philippe Deléham, Dec 14 2009

A326925 Irregular triangular array read by rows: row n shows the coefficients of this polynomial of degree n: (1/n!)*(numerator of n-th derivative of (1-x)/(1-x-x^2)).

Original entry on oeis.org

1, -1, 0, 2, -1, 1, 0, 3, -1, 1, 4, 0, 4, -1, 2, 5, 10, 0, 5, -1, 3, 12, 15, 20, 0, 6, -1, 5, 21, 42, 35, 35, 0, 7, -1, 8, 40, 84, 112, 70, 56, 0, 8, -1, 13, 72, 180, 252, 252, 126, 84, 0, 9, -1, 21, 130, 360, 600, 630, 504, 210, 120, 0, 10, -1, 34, 231, 715
Offset: 1

Views

Author

Clark Kimberling, Oct 22 2019

Keywords

Comments

Column 1: Fibonacci numbers, F(m), for m >= -1, as in A000045. For n >= 0, the n-th row sum = F(2n), as in A001906.
Conjecture: The odd degree polynomials are irreducible; the even degree (= 2k) polynomials have exactly two irreducible factors, each of degree k.

Examples

			First 7 rows:
1    -1
0     2   -1
1     0    3   -1
1     4    0    4   -1
2     5    0   10    5   -1
3    12   15   20    0    6   -1
5    21   42   35   35    0    7   -1
First 7 polynomials:
1 - x
2 x - x^2
1 + 3 x^2 - x^3
1 + 4 x + 4 x^3 - x^4
2 + 5 x + 10 x^2 + 5 x^4 - x^5
3 + 12 x + 15 x^2 + 20 x^3 + 6 x^5 - x^6
5 + 21 x + 42 x^2 + 35 x^3 + 35 x^4 + 7 x^6 - x^7
Factorizations of even-degree polynomials:
degree 2:  (2 - x)*x
degree 4:  (1 + x^2)*(1 + 4x - x^2)
degree 6:  (1 + 3x + x^3)*(3 + 3x + 6x^2 - x^3)
degree 8:  (2 + 4x + 6x^2 + x^4)*(4 + 12 x + 6x^2 + 8x^3 - x^4)
degree 10: (3 + 10 x + 10 x^2 + 10 x^3 + x^5)*(7 + 20 x + 30 x^2 + 10 x^3 + 10 x^4 - x^5)
It appears that the constant terms of the factors are Fibonacci numbers (A000045) and Lucas numbers (A000032).
		

Crossrefs

Programs

  • Mathematica
    g[x_, n_] := Numerator[(-1)^(n + 1) Factor[D[(1 - x)/(1 - x - x^2), {x, n}]]]
    Column[Expand[Table[g[x, n]/n!, {n, 0, 12}]]] (* polynomials *)
    h[n_] := CoefficientList[g[x, n]/n!, x] (* A326925 *)
    Table[h[n], {n, 0, 10}]
    Column[%]

Formula

G.f. as array: ((y^2 + y - 1)*x - y + 1)/(1 + (y^2 + y - 1)*x^2 + (-2*y - 1)*x). - Robert Israel, Oct 31 2019

A081571 Sixth binomial transform of F(n+1).

Original entry on oeis.org

1, 7, 50, 363, 2669, 19814, 148153, 1113615, 8402722, 63577171, 481991621, 3659227062, 27808295345, 211479529943, 1609093780114, 12247558413819, 93245414394973, 710040492168070, 5407464407991017, 41185377124992351, 313703861897268866, 2389549742539808867
Offset: 0

Views

Author

Paul Barry, Mar 22 2003

Keywords

Comments

Binomial transform of A081570.
Case k=6 of family of recurrences a(n) = (2k+1)*a(n-1) - A028387(k-1)*a(n-2), a(0)=1, a(1)=k+1.

Crossrefs

Programs

  • GAP
    a:=[1,7];; for n in [3..30] do a[n]:=13*a[n-1]-41*a[n-2]; od; a; # G. C. Greubel, Aug 12 2019
  • Magma
    I:=[1, 7]; [n le 2 select I[n] else 13*Self(n-1)-41*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Aug 09 2013
    
  • Maple
    seq(coeff(series((1-6*x)/(1-13*x+41*x^2), x, n+1), x, n), n = 0..30); # G. C. Greubel, Aug 12 2019
  • Mathematica
    CoefficientList[Series[(1-6x)/(1 -13x +41x^2), {x, 0, 30}], x] (* Vincenzo Librandi, Aug 09 2013 *)
  • PARI
    my(x='x+O('x^30)); Vec((1-6*x)/(1-13*x+41*x^2)) \\ G. C. Greubel, Aug 12 2019
    
  • Sage
    def A081571_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P((1-6*x)/(1-13*x+41*x^2)).list()
    A081571_list(30) # G. C. Greubel, Aug 12 2019
    

Formula

a(n) = 13*a(n-1) - 41*a(n-2), a(0)=1, a(1)=7.
a(n) = (1/2 - sqrt(5)/10)*(13/2 - sqrt(5)/2)^n + (sqrt(5)/10 + 1/2)*(sqrt(5)/2 + 13/2)^n.
G.f.: (1 - 6*x)/(1 - 13*x + 41*x^2).
a(n) = Sum_{k=0..n} A094441(n,k)*6^k. - Philippe Deléham, Dec 14 2009
E.g.f.: exp(13*x/2)*(5*cosh(sqrt(5)*x/2) + sqrt(5)*sinh(sqrt(5)*x/2))/5. - Stefano Spezia, Mar 30 2023
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