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.

A139375 A Fibonacci-Catalan triangle. Also called the Fibonacci triangle.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 3, 5, 3, 1, 5, 12, 9, 4, 1, 8, 31, 26, 14, 5, 1, 13, 85, 77, 46, 20, 6, 1, 21, 248, 235, 150, 73, 27, 7, 1, 34, 762, 741, 493, 258, 108, 35, 8, 1, 55, 2440, 2406, 1644, 903, 410, 152, 44, 9, 1, 89, 8064, 8009
Offset: 0

Views

Author

Paul Barry, Apr 15 2008

Keywords

Comments

First column is the Fibonacci numbers A000045(n+1). The second column is A090826.
Row sums are A090826(n+1). Diagonal sums are A139376. Inverse array is (1 - x + 2x^3 - x^4, x(1-x)), A201167.
Essentially A185937 with trailing zeros removed. - Ralf Stephan, Jan 01 2014

Examples

			Triangle begins
1,
1, 1,
2, 2, 1,
3, 5, 3, 1,
5, 12, 9, 4, 1,
8, 31, 26, 14, 5, 1,
13, 85, 77, 46, 20, 6, 1,
21, 248, 235, 150, 73, 27, 7, 1,
34, 762, 741, 493, 258, 108, 35, 8, 1
The production matrix for this array is
1, 1,
1, 1, 1,
-1, 1, 1, 1,
0, 1, 1, 1, 1,
0, 1, 1, 1, 1, 1,
0, 1, 1, 1, 1, 1, 1,
0, 1, 1, 1, 1, 1, 1
		

Programs

  • Maple
    RIORDAN := proc(d,h,n,k)
        d*h^k ;
        expand(%) ;
        coeftayl(%,x=0,n) ;
    end proc:
    A139375 := proc(n,k)
        RIORDAN(1/(1-x-x^2),(1-sqrt(1-4*x))/2,n,k) ;
    end proc: # R. J. Mathar, Jul 09 2013
  • Mathematica
    T[n_, 0]:= Fibonacci[n + 1]; T[n_, k_]:= k*Sum[Fibonacci[i + 1]*Binomial[2*(n - i) - k - 1, n - i - 1]/(n - i), {i, 0, n - k}]; Table[T[n, k], {n, 0, 49}, {k, 0, n}] // Flatten (* G. C. Greubel, Oct 20 2016 *)

Formula

Riordan array (1/(1-x-x^2), xc(x)), c(x) the g.f. of A000108.
T(n,k) = k * Sum_{i=0..n-k} (Fibonacci(i+1)*binomial(2*(n-i)-k-1,n-i-1)/(n-i)) if k>0, and Fibonacci(n+1) if k=0. - Vladimir Kruchinin, Mar 09 2011

Extensions

Alternative name added by N. J. A. Sloane, Nov 27 2011

A089867 Permutation of natural numbers induced by the Catalan bijection gma089867 acting on the parenthesizations/binary trees encoded by A014486/A063171.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 49, 51, 52, 53, 54, 55, 60, 61, 64, 63, 56, 57, 59, 58, 62, 65, 66, 67, 68, 69
Offset: 0

Views

Author

Antti Karttunen, Dec 20 2003

Keywords

Comments

This Catalan bijection arises when we apply the Catalan bijection A085169 to the left subtree and keep the right subtree intact.

Crossrefs

Inverse of A089868.
Number of cycles: A089846. Number of fixed-points: A090826. Max. cycle size: A086586. LCM of cycle sizes: A086587. (In range [A014137(n-1)..A014138(n-1)] of this permutation, possibly shifted one term left or right).

A089868 Permutation of natural numbers induced by the Catalan bijection gma089868 acting on the parenthesizations/binary trees encoded by A014486/A063171.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 49, 51, 52, 53, 54, 55, 60, 61, 63, 62, 56, 57, 64, 59, 58, 65, 66, 67, 68, 69
Offset: 0

Views

Author

Antti Karttunen, Dec 20 2003

Keywords

Comments

This Catalan bijection arises when we apply the Catalan bijection A085170 to the left subtree and keep the right subtree intact.

Crossrefs

Inverse of A089867.
Number of cycles: A089846. Number of fixed-points: A090826. Max. cycle size: A086586. LCM of cycle sizes: A086587. (In range [A014137(n-1)..A014138(n-1)] of this permutation, possibly shifted one term left or right).

A277220 Exponential convolution of Fibonacci (A000045) and Catalan (A000108) numbers.

Original entry on oeis.org

0, 1, 3, 11, 43, 180, 790, 3590, 16745, 79705, 385615, 1890747, 9375216, 46931897, 236873261, 1204089630, 6159064015, 31678706490, 163739008070, 850051218980, 4430529313065, 23175017046351, 121617754070653, 640122809255716, 3378402106118508, 17875011275340275
Offset: 0

Views

Author

Vladimir Reshetnikov, Oct 06 2016

Keywords

Crossrefs

Programs

  • Magma
    [(&+[Binomial(n,k)*Fibonacci(k)*Catalan(n-k): k in [0..n]]): n in [0..30]]; // G. C. Greubel, Oct 22 2018
  • Mathematica
    Table[Sum[Binomial[n, k] Fibonacci[k] CatalanNumber[n - k], {k, 0, n}], {n, 0, 30}] (* or *)
    Round@Table[(GoldenRatio^n Hypergeometric2F1[1/2, -n, 2, -4/GoldenRatio] - (-GoldenRatio)^(-n) Hypergeometric2F1[1/2, -n, 2, 4 GoldenRatio])/Sqrt[5], {n, 0, 30}] (* Round is equivalent to FullSimplify here, but is much faster *)
  • PARI
    for(n=0, 30, print1(sum(k=0,n, binomial(n,k)*fibonacci(k)* binomial(2*n-2*k,n-k)/(n-k+1)), ", ")) \\ G. C. Greubel, Oct 22 2018
    

Formula

a(n) = Sum_{k=0..n} binomial(n,k) * A000045(k) * A000108(n-k).
a(n) = (phi^n * hypergeom([1/2, -n], [2], -4/phi) - (-phi)^(-n) * hypergeom([1/2, -n], [2], 4*phi))/sqrt(5), where phi = (1+sqrt(5))/2 = A001622.
Recurrence: 19*(n+1)*(n+2)*(11*n+13)*a(n) + 2*(55*n^3+208*n^2+311*n+230)*a(n+1) + 2*(55*n^3+373*n^2+674*n+206)*a(n+3) = (n+2)*(297*n^2+1022*n+617)*a(n+2) + (n+3)*(n+5)*(11*n+2)*a(n+4).
E.g.f.: 2*exp(5*x/2)*sinh(x*sqrt(5)/2)*(BesselI_0(2*x) - BesselI_1(2*x))/sqrt(5) (the product of e.g.f. for Fibonacci and Catalan numbers).
a(n) ~ (phi + 4)^(n + 3/2) / (8 * sqrt(5*Pi) * n^(3/2)), where phi = A001622 = (1 + sqrt(5))/2 is the golden ratio. - Vaclav Kotesovec, Mar 10 2018

A277251 Exponential convolution of Lucas (A000032) and Catalan (A000108) numbers.

Original entry on oeis.org

2, 3, 9, 29, 107, 430, 1840, 8230, 38015, 179873, 867079, 4242111, 21006358, 105072063, 530058079, 2693632580, 13775807415, 70847283680, 366167521240, 1900884870494, 9907318315587, 51822028122623, 271949090063769, 1431369293422604, 7554372307564282
Offset: 0

Views

Author

Vladimir Reshetnikov, Oct 06 2016

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[Binomial[n, k] LucasL[k] CatalanNumber[n - k], {k, 0, n}], {n, 0,
       30}] (* or *)
    Round@Table[GoldenRatio^n Hypergeometric2F1[1/2, -n, 2, -4/GoldenRatio] + (-GoldenRatio)^(-n) Hypergeometric2F1[1/2, -n, 2, 4 GoldenRatio], {n, 0, 30}] (* Round is equivalent to FullSimplify here, but is much faster *)

Formula

a(n) = Sum_{k=0..n} binomial(n,k) * A000032(k) * A000108(n-k).
a(n) = phi^n * hypergeom([1/2, -n], [2], -4/phi) + (-phi)^(-n) * hypergeom([1/2, -n], [2], 4*phi), where phi = (1+sqrt(5))/2 = A001622.
Recurrence: 19*(n+1)*(n+2)*(11*n+13)*a(n) + 2*(55*n^3+208*n^2+311*n+230)*a(n+1) + 2*(55*n^3+373*n^2+674*n+206)*a(n+3) = (n+2)*(297*n^2+1022*n+617)*a(n+2) + (n+3)*(n+5)*(11*n+2)*a(n+4).
E.g.f.: 2*exp(5*x/2)*cosh(x*sqrt(5)/2)*(BesselI_0(2*x) - BesselI_1(2*x)) (the product of e.g.f. for Lucas and Catalan numbers).
a(n) ~ (phi + 4)^(n + 3/2) / (8 * sqrt(Pi) * n^(3/2)), where phi = A001622 = (1 + sqrt(5))/2 is the golden ratio. - Vaclav Kotesovec, Mar 10 2018
Showing 1-5 of 5 results.