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 1-3 of 3 results.

A193999 Mirror of the triangle A094585.

Original entry on oeis.org

1, 3, 2, 6, 5, 3, 11, 10, 8, 5, 19, 18, 16, 13, 8, 32, 31, 29, 26, 21, 13, 53, 52, 50, 47, 42, 34, 21, 87, 86, 84, 81, 76, 68, 55, 34, 142, 141, 139, 136, 131, 123, 110, 89, 55, 231, 230, 228, 225, 220, 212, 199, 178, 144, 89, 375, 374, 372, 369, 364, 356, 343
Offset: 1

Views

Author

Clark Kimberling, Aug 11 2011

Keywords

Comments

A193999 is obtained by reversing the rows of the triangle A094585.

Examples

			First six rows:
   1;
   3,  2;
   6,  5,  3;
  11, 10,  8,  5;
  19, 18, 16, 13,  8;
  32, 31, 29, 26, 21, 13;
		

Crossrefs

Cf. A094585.

Programs

  • GAP
    Flat(List([1..11],n->Reversed(List([1..n],k->Fibonacci(n+3)-Fibonacci(n-k+3))))); # Muniru A Asiru, Apr 28 2019
  • Mathematica
    z = 11;
    p[n_, x_] := Sum[Fibonacci[k + 1]*x^(n - k), {k, 0, n}];
    q[n_, x_] := x*q[n - 1, x] + 1; q[0, n_] := 1;
    p1[n_, k_] := Coefficient[p[n, x], x^k];
    p1[n_, 0] := p[n, x] /. x -> 0;
    d[n_, x_] := Sum[p1[n, k]*q[n - 1 - k, x], {k, 0, n - 1}]
    h[n_] := CoefficientList[d[n, x], {x}]
    TableForm[Table[Reverse[h[n]], {n, 0, z}]]
    Flatten[Table[Reverse[h[n]], {n, -1, z}]]  (* A094585 *)
    TableForm[Table[h[n], {n, 0, z}]]
    Flatten[Table[h[n], {n, -1, z}]]  (* A193999 *)
    (* alternate program *)
    Table[Fibonacci[n+3]-Fibonacci[k+2], {n,1,10}, {k,1,n}] //TableForm (* Rigoberto Florez, Oct 03 2019 *)

Formula

Write w(n,k) for the triangle at A094585. The triangle at A094585 is then given by w(n,n-k).
T(n,k) = Fibonacci(n+3) - Fibonacci(k+2) for n > 0 and 1 <= k <= n. - Rigoberto Florez, Oct 03 2019
G.f.: x*y*(x*y+x+1)/((1-x)*(x^2+x-1)*(x^2*y^2+x*y-1)). - Vladimir Kruchinin, Jun 20 2025

Extensions

Offset 1 from Muniru A Asiru, Apr 29 2019

A094584 Dot product of (1,2,...,n) and first n distinct Fibonacci numbers.

Original entry on oeis.org

1, 5, 14, 34, 74, 152, 299, 571, 1066, 1956, 3540, 6336, 11237, 19777, 34582, 60134, 104062, 179320, 307855, 526775, 898706, 1529160, 2595624, 4396224, 7431049, 12537917, 21118814, 35517226, 59646386, 100034456, 167562035, 280348531, 468543802, 782277612
Offset: 1

Views

Author

Clark Kimberling, May 13 2004

Keywords

Comments

a(n) is the cost of all non-leaf nodes in the Fibonacci tree of order n+2. A Fibonacci tree of order n (n>=2) is a complete binary tree whose left subtree is the Fibonacci tree of order n-1 and whose right subtree is the Fibonacci tree of order n-2; each of the Fibonacci trees of order 0 and 1 is defined as a single node. In a Fibonacci tree the cost of a left (right) edge is defined to be 1 (2). The cost of a node of a Fibonacci tree is defined to be the sum of the costs of the edges that form the path from the root to this node. - Emeric Deutsch, Jun 14 2010

Examples

			a(4) = (1,2,3,4)*(1,2,3,5) = 1+4+9+20 = 34.
		

References

  • A. T. Benjamin and J. J. Quinn, Proofs that really count: the art of combinatorial proof, M.A.A. 2003, p. 14.
  • D. E. Knuth, The Art of Computer Programming, Vol. 3, 2nd edition, Addison-Wesley, Reading, MA, 1998, p. 417. [From Emeric Deutsch, Jun 14 2010]

Crossrefs

Partial sums of A023607.

Programs

  • GAP
    List([1..40],n->(n+1)*Fibonacci(n+3)-Fibonacci(n+5)+3); # Muniru A Asiru, Apr 27 2019
    
  • Magma
    I:=[1,5,14,34,74]; [n le 5 select I[n] else 3*Self(n-1)-Self(n-2)-3*Self(n-3)+Self(n-4)+Self(n-5): n in [1..40]]; // Vincenzo Librandi, Mar 11 2015
    
  • Magma
    [n*Fibonacci(n+3)-Fibonacci(n+4)+3: n in [1..40]]; // G. C. Greubel, Apr 28 2019
    
  • Maple
    with(combinat): A094584:=n->(n+1)*fibonacci(n+3)-fibonacci(n+5)+3: seq(A094584(n), n=1..50); # Wesley Ivan Hurt, Mar 10 2015
  • Mathematica
    Table[Range[n].Fibonacci[Range[2,n+1]],{n,40}] (* Harvey P. Dale, Aug 21 2011 *)
  • PARI
    {a(n) = n*fibonacci(n+3) - fibonacci(n+4) +3}; \\ G. C. Greubel, Apr 28 2019
    
  • Sage
    [n*fibonacci(n+3) - fibonacci(n+4) +3 for n in (1..40)] # G. C. Greubel, Apr 28 2019

Formula

a(n) = F(2) + 2*F(3) + 3*F(4) + ... + n*F(n+1) = (n+1)*F(n+3) - F(n+5) + 3.
G.f.: x*(1+2*x)/((1-x)*(1-x-x^2)^2). - Colin Barker, Nov 11 2012
From Wesley Ivan Hurt, Mar 10 2015: (Start)
a(n) = 3*a(n-1) - a(n-2) - 3*a(n-3) + a(n-4) + a(n-5).
a(n) = Sum_{i=1..n+2} (n-i+1) * F(n-i+2).
a(n) = (30*(-1-sqrt(5))^n + (-15+7*sqrt(5))*2^n - (15+7*sqrt(5))*(-3-sqrt(5))^n + 2n*((5-2*sqrt(5))*2^n + (5+2*sqrt(5))*(-3-sqrt(5))^n)) / (10*(-1-sqrt(5))^n). (End)

A094586 Central numbers of the triangle T of all positive differences of distinct Fibonacci numbers.

Original entry on oeis.org

1, 5, 16, 47, 131, 356, 953, 2529, 6676, 17567, 46135, 121016, 317201, 831053, 2176712, 5700303, 14926171, 39081404, 102323209, 267896585, 701380076, 1836265535, 4807451951, 12586147632, 32951083681, 86267253461, 225850919488
Offset: 1

Views

Author

Clark Kimberling, May 13 2004

Keywords

Comments

As T is also the triangle of sums of consecutive distinct Fibonacci numbers, a(n) is such a sum, namely Sum_{j=n+1..2n} Fibonacci(j).

Examples

			a(4) = F(10)-F(6) = 55-8 = 47.
		

Crossrefs

Programs

  • GAP
    List([1..30],n->Fibonacci(2*n+2)-Fibonacci(n+2)); # Muniru A Asiru, Apr 28 2019
    
  • Magma
    F:=Fibonacci; [F(2*n+2)-F(n+2): n in [1..30]]; // G. C. Greubel, Jul 14 2019
    
  • Mathematica
    Table[Sum[Fibonacci[n+i], {i,n}], {n,30}] (* Zerinvary Lajos, Jul 12 2009 *)
    With[{F=Fibonacci}, Table[F[2n+2]-F[n+2], {n,30}]] (* G. C. Greubel, Jul 14 2019 *)
    LinearRecurrence[{4,-3,-2,1},{1,5,16,47},30] (* Harvey P. Dale, Dec 31 2024 *)
  • PARI
    vector(30, n, f=fibonacci; f(2*n+2)-f(n+2)) \\ G. C. Greubel, Jul 14 2019
    
  • Sage
    f=fibonacci; [f(2*n+2)-f(n+2) for n in (1..30)] # G. C. Greubel, Jul 14 2019

Formula

a(n) = Fibonacci(2n+2) - Fibonacci(n+2) = A094585(2n-1, n).
G.f.: x*(1+x-x^2)/((1-x-x^2)*(1-3*x+x^2)). - Colin Barker, Sep 16 2012
Showing 1-3 of 3 results.