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 1-2 of 2 results.

A046814 Row sums of triangle A046527.

Original entry on oeis.org

1, 2, 8, 37, 179, 881, 4369, 21746, 108444, 541362, 2704158, 13512392, 67534828, 337584992, 1687627800, 8437136085, 42182258715, 210899507685, 1054456597965, 5272139698215, 26360193558735, 131799177579015
Offset: 0

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Crossrefs

Programs

  • Magma
    [n le 1 select 1 else 5*Self(n-1) - 3*Catalan(n-1)/(2*n-3): n in [1..40]]; // G. C. Greubel, Jul 28 2024
    
  • Mathematica
    CoefficientList[Series[(1-4*x)*(1-Sqrt[1-4*x])/(2*x*(1-5*x)), {x,0,40}], x] (* G. C. Greubel, Jul 28 2024 *)
  • SageMath
    @CachedFunction
    def A046814(n): return 1 if n==0 else 5*A046814(n-1) - 3*catalan_number(n)/(2*n-1)
    [A046814(n) for n in range(41)] # G. C. Greubel, Jul 28 2024

Formula

G.f.: c(x) * (1-4*x) / (1-5*x), where c(x) = g.f. for Catalan A000108.
a(n) = C(n) + A046714(n-1) with A046714(-1) = 0 and C(n) = A000108(n) are the Catalan numbers.
a(n) = C(n) + (5^n - A046748(n))/2.
a(n) = 5*a(n-1) - 3*C(n)/(2*n-1), a(0)=1.
D-finite with recurrence a(n) = (9*n-1)*a(n-1)/(n+1) - 10*(2*n-3)*a(n-2)/(n+1), n >= 2, a(0)=1, a(1)=2.

Extensions

Offset corrected by Sean A. Irvine, Apr 25 2021

A048870 Triangle of coefficients of certain Sheffer-polynomials.

Original entry on oeis.org

1, 1, 1, 4, 10, 1, 30, 132, 27, 1, 336, 2232, 696, 52, 1, 5040, 46320, 19500, 2200, 85, 1, 95040, 1141920, 606960, 91800, 5340, 126, 1, 2162160, 32639040, 20991600, 3986640, 310170, 11004, 175, 1, 57657600, 1061746560, 802287360, 183550080
Offset: 0

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Comments

s(n,x) := sum(a(n,m)*x^m,m=0..n) are monic polynomials satisfying s(n,x+y) = sum(binomial(n,k)*s(k,x)*p(n-k,y),k=0..n), with polynomials p(n,x)=sum(A048786(n,m)*x^m, m=1..n) (row polynomials of triangle A048786) and p(0,x)=1. In the umbral calculus (see reference) the s(n,x) are called Sheffer polynomials for(c(t/(1+4*t)),t/(1+4*t)), where c(x) = g.f. for Catalan numbers A000108. a(n,0) = A001761(n-2) = n!*A000108(n).

References

  • S. Roman, The Umbral Calculus, Academic Press, New York, 1984.

Crossrefs

Formula

a(n, m) = (n!/m!)*A046527(n, m) = (n!/m!)*binomial(n, m-1)*(4^(n-m+1)-binomial(2*n, n)/binomial(2*(m-1), m-1))/2, n >= m >= 0, a(n, m) := 0, n
Showing 1-2 of 2 results.