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.

A110326 Diagonal sums of triangle A110324.

Original entry on oeis.org

1, -1, -3, -2, -11, -3, -23, -4, -39, -5, -59, -6, -83, -7, -111, -8, -143, -9, -179, -10, -219, -11, -263, -12, -311, -13, -363, -14, -419, -15, -479, -16, -543, -17, -611, -18, -683, -19, -759, -20, -839, -21, -923, -22, -1011, -23, -1103, -24, -1199, -25, -1299, -26, -1403, -27, -1511, -28, -1623, -29, -1739
Offset: 0

Views

Author

Paul Barry, Jul 20 2005

Keywords

Formula

G.f.: (1-x-6x^2+x^3+x^4)/((1+x)^3(1-x)^3); a(n)=3a(n-2)-3a(n-4)+a(n-6); a(n)=-(n^2+3n-1)/4-(n^2+n-3)(-1)^n/4.

A110321 A Jacobsthal number related number triangle.

Original entry on oeis.org

1, 1, 1, 6, 2, 1, 30, 18, 3, 1, 264, 120, 36, 4, 1, 2520, 1320, 300, 60, 5, 1, 30960, 15120, 3960, 600, 90, 6, 1, 428400, 216720, 52920, 9240, 1050, 126, 7, 1, 6894720, 3427200, 866880, 141120, 18480, 1680, 168, 8, 1, 123742080, 62052480, 15422400, 2600640
Offset: 0

Views

Author

Paul Barry, Jul 20 2005

Keywords

Examples

			Rows begin
  1;
  1,1;
  6,2,1;
  30,18,3,1;
  264,120,36,4,1;
  2520,1320,300,60,5,1;
  30960,15120,3960,600,90,6,1;
		

Crossrefs

Row sums are A110322.
Antidiagonal sums are A110323.
Inverse is A110324.

Formula

T(n,k) = n!*J(n-k+1)/k!, where J(n)=A001045(n).
Column k has e.g.f. (x^k/k!)/(1-x-2x^2).

A110325 Row sums of number triangle related to the Jacobsthal numbers.

Original entry on oeis.org

1, 0, -5, -14, -27, -44, -65, -90, -119, -152, -189, -230, -275, -324, -377, -434, -495, -560, -629, -702, -779, -860, -945, -1034, -1127, -1224, -1325, -1430, -1539, -1652, -1769, -1890, -2015, -2144, -2277, -2414, -2555, -2700, -2849, -3002, -3159, -3320, -3485, -3654, -3827, -4004, -4185, -4370
Offset: 0

Views

Author

Paul Barry, Jul 20 2005

Keywords

Comments

Essentially the same sequence as A014106.
Rows sums of A110324. Results from a general construction: the row sums of the inverse of the number triangle whose columns have e.g.f. (x^k/k!)/(1 - a*x - b*x^2), g.f. (1 - (a+2)*x - (2*b-a-1)*x^2)/(1-x)^3, and general term 1 + (b-a)*n - b*n^2. This is the binomial transform of (1, -a, -2b, 0, 0, 0, ...).

Crossrefs

Cf. A014106 (essentially the same sequence), A110324.

Programs

Formula

a(n) = 1 + n - 2*n^2.
G.f.: (1 - 3*x - 2*x^2)/(1-x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Vincenzo Librandi, Jul 08 2012
From Elmo R. Oliveira, Nov 02 2024: (Start)
E.g.f.: exp(x)*(1 - x - 2*x^2).
a(n) = -A005408(n)*A110325(n). (End)
Showing 1-3 of 3 results.