A296056 Determinant of the inverse of the matrix A_n, where A_n is the n X n matrix defined by A_n[i,j] = 1/C(i+j-2) for 1 <= i,j <= n, and C(k) is the k-th Catalan number (A000108).

1, -2, -1400, -679140000, -122489812645200000, -6931927717187904217987200000, -114287375178291587421201860354580633600000, -527655997339226839875614785993553970321322576128000000000, -666218073328701414704702576237379472614149140939534461737723520000000000000

Offset

1,2

Comments

It is conjectured that a(n) is an integer for all n.

The contributor suggests the name "Catbert matrix" for the matrix A_n, based on its similarity to the Hilbert matrix and its relation to the Catalan numbers.

Links

Tom Richardson, Table of n, a(n) for n = 1..29

Tom Richardson, Table of n, a(n) for n = 1..100

Thomas M. Richardson, Catalan Numbers and Jacobi Polynomials, arXiv:2005.08939 [math.CO], 2020.

Formula

a(n) ~ -c * 16^(n*(n-1)) / (3^n * Pi^n * n^(27/8)), where c = 3*A^(3/2) / (2^(7/6) * exp(1/8) * sqrt(Pi)) = 0.9662886794923866798595701447717791386557874..., where A is the Glaisher-Kinkelin constant A074962. - Vaclav Kotesovec, May 19 2020

Mathematica

a[n_] := 1/Det@ Table[ 1/CatalanNumber[i + j -2], {i, n}, {j, n}]; Array[a, 9] (* Robert G. Wilson v, Jan 05 2018 *)
Table[Product[4^(2*k + 1) * (4*k - 1)/6 * Binomial[2*k - 3/2, k] * Binomial[2*k - 3/2, k + 1], {k, 0, n - 1}], {n, 1, 10}] (* Vaclav Kotesovec, May 19 2020 *)

Prog

(PARI) a(n) = 1/matdet(matrix(n, n, i, j, (i+j-1)/binomial(2*i+2*j-4, i+j-2)))

Crossrefs

Cf. A000108, A005249, A062381.

Sequence in context: A350806 A135129 A212841 * A294089 A157494 A227247

Adjacent sequences: A296053 A296054 A296055 * A296057 A296058 A296059

Keyword

sign

Author

Tom Richardson, Dec 03 2017

Status

approved