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 1-4 of 4 results.

A067303 Even-indexed members of A067302.

Original entry on oeis.org

1, 18, 1752, 282304, 54547200, 11478167040, 2533556365312, 576271774875648, 133776598692003840, 31513560479297044480, 7505638177922587557888, 1802924878727702252617728, 436026430783762289982963712
Offset: 0

Views

Author

Wolfdieter Lang, Feb 05 2002

Keywords

Crossrefs

Cf. A067322 (odd-indexed members of A067302).

Formula

a(n) = A067302(2n) = (n+1)*A067297(2*n).
G.f.: (x*(d/dx)A(x) + A(x)) with A(x) g.f. of A067320.

A067322 Odd-indexed members of A067302.

Original entry on oeis.org

3, 160, 21504, 3867840, 785255680, 169748686848, 38094656593920, 8761529890717696, 2050020136793604096, 485760548730263568384, 116217935644216514314240, 28016590108689074277580800
Offset: 0

Views

Author

Wolfdieter Lang, Feb 05 2002

Keywords

Crossrefs

Cf. A067303 (even-indexed members of A067302).

Formula

a(n) = A067302(2n+1) = (2*n+3)*A067297(2*n+1)/2.
G.f.: A(x) = (2*x*(d/dx)g(x) + 3*g(x)) with g(x) g.f. of A067321.

A067304 Generalized Catalan triangle A067298 with row reversion.

Original entry on oeis.org

1, 2, 1, 9, 5, 4, 64, 36, 32, 28, 584, 328, 300, 284, 256, 6144, 3440, 3184, 3072, 2960, 2704, 70576, 39408, 36704, 35680, 34896, 33872, 31168, 859520, 478912, 447744, 436928, 429760, 422592, 411776, 380608, 10909440, 6068480, 5687872, 5563200, 5487488, 5421952, 5346240, 5221568, 4840960
Offset: 0

Views

Author

Wolfdieter Lang, Feb 05 2002

Keywords

Comments

Identity for each row n >= 1: T(n, m) + T(n, n-m+1) = A067297(n+1) (convolution of generalized Catalan numbers) for every m = 1..floor((n+1)/2). E.g., T(2*k+1, k+1) = A067297(2*(k+1))/2.

Examples

			Triangle begins:
    1;
    2,   1;
    9,   5,   4;
   64,  36,  32,  28;
  584, 328, 300, 284, 256;
  ...
n=3: T(3, 0) = 64 = 36+28 = 32+32.
		

Crossrefs

The columns give for m=0..4: A067297 (diagonals of A067298), A067305, A067306, A067307, A067308.
Cf. A067302 (row sums), A067323 (corresponding triangle for ordinary Catalan numbers).

Formula

T(n, m) = A067298(n, n-m), n >= m >= 0, otherwise 0.
G.f. for column m >= 1 (without leading zeros): (2^(2*ceiling(m/2))*p(m, y)*(y^3)/(1+y)^4, where y = y(x) = c(4*x), with c(x) = g.f. of A000108 (Catalan) and the row polynomials p(n, y) = Sum_{k=0..n} A067329(n, k)*y^k, n >= 1. For m = 0: ((y*(3+y))^2)/(1+y)^4 with y = y(x) = c(4*x) (see A067297).

Extensions

More terms from Jinyuan Wang, Apr 20 2025

A067298 Generalized Catalan triangle, based on C(2,2; n) = A064340(n).

Original entry on oeis.org

1, 1, 2, 4, 5, 9, 28, 32, 36, 64, 256, 284, 300, 328, 584, 2704, 2960, 3072, 3184, 3440, 6144, 31168, 33872, 34896, 35680, 36704, 39408, 70576, 380608, 411776, 422592, 429760, 436928, 447744, 478912, 859520, 4840960, 5221568, 5346240, 5421952, 5487488, 5563200, 5687872, 6068480, 10909440
Offset: 0

Views

Author

Wolfdieter Lang, Feb 05 2002

Keywords

Comments

For corresponding Catalan triangle with C(1,1; n) = A000108(n) see A028364.
Identity for each row n>=1: T(n, m) + T(n, n-(m+1)) = T(n, n) = A067297(n) for m=0..floor((n-1)/2). E.g., T(2*k+1, k) = A067297(2*k+1)/2.

Examples

			Triangle begins:
    1;
    1,   2;
    4,   5,   9;
   28,  32,  36,  64;
  256, 284, 300, 328, 584;
  ...
		

Crossrefs

The columns (without leading zeros) give for m=0..3: A064340, A067299, 3*A067300, 8*A067301.
The main diagonal gives A067297. The row sums give A067302.

Programs

  • PARI
    A064340(n) = if(n>1, sum(m=0, n-2, (m+1)*(m+2)*binomial(2*(n-2)-m, n-2-m)/2^(m+1))*(4^(n-1))/(n-1), 1);
    T(n, m) = sum(i=0, m, A064340(i)*A064340(n-i)); \\ Jinyuan Wang, Apr 20 2025

Formula

T(n, m) = Sum_{i=0..m} C(2,2; i)*C(2,2; n-i) if n >= m >= 0 else 0.
G.f. for column m (without leading zeros): (c(m, x)*c(2,2; x)-c2(m-1, x))/x^m, with c(2,2; x) = (1-3*x*c(4*x))/(1-2*x*c(4*x))^2 (g.f. for C(2,2; n)), c(x) = g.f. for Catalan numbers A000108, c(m, x) = Sum_{n=0..m} C(2,2; n)*x^n and c2(m, x) = Sum_{n=0..m} A067297(n)*x^n for m=0, 1, 2, ...

Extensions

More terms from Jinyuan Wang, Apr 20 2025
Showing 1-4 of 4 results.