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.

A145362 Lower triangular array S1hat(-1) read by rows, related to partition number array A145361.

Original entry on oeis.org

1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1
Offset: 1

Views

Author

Wolfdieter Lang, Oct 17 2008

Keywords

Comments

If in the partition array M31hat(-1):=A145361 entries belonging to partitions with the same parts number m are summed one obtains this triangle of numbers S1hat(-1). In the same way the signless Stirling1 triangle |A008275| is obtained from the partition array M_2 = A036039.
The first column is [1,1,0,0,0,...]=A008279(1,n-1), n>=1.
T(n,m) gives the number of partitions of n with m parts, with each part not exceeding 2. - Wolfdieter Lang, Aug 03 2023

Examples

			Triangle begins:
  [1];
  [1,1];
  [0,1,1];
  [0,1,1,1];
  [0,0,1,1,1];
  [0,0,1,1,1,1];
  ...
		

Crossrefs

Cf. A004526(n+2), n>=1, (row sums).
Cf. A008275, A008279, A008284, A036039, A145361, A339884 (parts <=3), A232539 (parts <=4).

Programs

Formula

T(n,m) = Sum_{q=1..p(n,m)} Product_{j=1..n} S1(-1;j,1)^e(n,m,q,j) if n>=m>=1, else 0. Here p(n,m) = A008284(n,m), the number of m parts partitions of n and e(n,m,q,j) is the exponent of j in the q-th m part partition of n. S1(-1;n,1) = A008279(1,n-1) = [1,1,0,0,0,...], n>=1.
The triangle starts in row n with ceiling(n/2) - 1 zeros, and is 1 otherwise. - Wolfdieter Lang, Aug 03 2023
G.f.: 1/((1-u*t)*(1-u*t^2)). [Comtet page 97 [2c]]. - R. J. Mathar, May 27 2025

A339884 Triangle read by rows: T(n, m) gives the number of partitions of n with m parts and parts from {1, 2, 3}.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 0, 2, 1, 1, 0, 1, 2, 1, 1, 0, 1, 2, 2, 1, 1, 0, 0, 2, 2, 2, 1, 1, 0, 0, 1, 3, 2, 2, 1, 1, 0, 0, 1, 2, 3, 2, 2, 1, 1, 0, 0, 0, 2, 3, 3, 2, 2, 1, 1, 0, 0, 0, 1, 3, 3, 3, 2, 2, 1, 1, 0, 0, 0, 1, 2, 4, 3, 3, 2, 2, 1, 1
Offset: 1

Views

Author

Wolfdieter Lang, Jan 31 2021

Keywords

Comments

Row sums give A001399(n), for n >= 1.
One could add the column [1,repeat 0] for m = 0 starting with n >= 0.

Examples

			The triangle T(n,m) begins:
  n\m  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 ...
  1:   1
  2:   1 1
  3:   1 1 1
  4:   0 2 1 1
  5:   0 1 2 1 1
  6:   0 1 2 2 1 1
  7:   0 0 2 2 2 1 1
  8:   0 0 1 3 2 2 1 1
  9:   0 0 1 2 3 2 2 1 1
  10:  0 0 0 2 3 3 2 2 1  1
  11:  0 0 0 1 3 3 3 2 2  1  1
  12:  0 0 0 1 2 4 3 3 2  2  1  1
  13:  0 0 0 0 2 3 4 3 3  2  2  1  1
  14:  0 0 0 0 1 3 4 4 3  3  2  2  1  1
  15:  0 0 0 0 1 2 4 4 4  3  3  2  2  1  1
  16:  0 0 0 0 0 2 3 5 4  4  3  3  2  2  1  1
  17:  0 0 0 0 0 1 3 4 5  4  4  3  3  2  2  1  1
  18:  0 0 0 0 0 1 2 4 5  5  4  4  3  3  2  2  1  1
  19:  0 0 0 0 0 0 2 3 5  5  5  4  4  3  3  2  2  1  1
  20:  0 0 0 0 0 0 1 3 4  6  5  5  4  4  3  3  2  2  1  1
  ...
Row n = 6: the partitions of 6 with number of parts m = 1,2, ...., 6, and parts from {1,2,3} are (in Abramowitz-Stegun order): [] | [],[],[3,3] | [],[1,2,3],[2^3] | [1^3,3],[1^2,2^2] | [1^4,2] | 1^6, giving 0, 1, 2, 2, 1, 1.
		

Crossrefs

Cf. A001399, A008284 (all parts), A145362 (parts 1, 2), A232539 (parts <=4), A291983.
Compositions: A007818, A030528 (parts 1, 2), A078803 (parts 1, 2, 3).

Formula

Sum_{k=0..n} (-1)^k * T(n,k) = A291983(n). - Alois P. Heinz, Feb 01 2021
G.f.: 1/((1-u*t)*(1-u*t^2)*(1-u*t^3)). [Comtet page 97 [2c]]. - R. J. Mathar, May 27 2025

A233292 Triangle read by rows: T(n,k) is the number of partitions of n into at most four parts in which no part exceeds k, 0 <= k <= n.

Original entry on oeis.org

1, 0, 1, 0, 1, 2, 0, 1, 2, 3, 0, 1, 3, 4, 5, 0, 0, 2, 4, 5, 6, 0, 0, 2, 5, 7, 8, 9, 0, 0, 1, 4, 7, 9, 10, 11, 0, 0, 1, 4, 8, 11, 13, 14, 15, 0, 0, 0, 3, 7, 11, 14, 16, 17, 18, 0, 0, 0, 2, 7, 12, 16, 19, 21, 22, 23, 0, 0, 0, 1, 5, 11, 16, 20, 23, 25, 26, 27, 0, 0, 0, 1, 5, 11, 18, 23, 27, 30, 32, 33, 34
Offset: 0

Views

Author

L. Edson Jeffery, Jan 02 2014

Keywords

Comments

Transpose of table A219237.

Examples

			Triangle T(n,k) begins:
1;
0, 1;
0, 1, 2;
0, 1, 2, 3;
0, 1, 3, 4, 5;
0, 0, 2, 4, 5,  6;
0, 0, 2, 5, 7,  8,  9;
0, 0, 1, 4, 7,  9, 10, 11;
0, 0, 1, 4, 8, 11, 13, 14, 15; ...
		

Crossrefs

Cf. A001400 (main diagonal), A219237, A232539.

Formula

T(n,k) = Sum_{j=0..k} A232539(n,j).
Showing 1-3 of 3 results.