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.

A210971 Triangle read by rows in which row n lists the region number of the parts of the k-th partition of n, with partitions reverse lexicographically ordered.

Original entry on oeis.org

1, 3, 2, 6, 5, 3, 11, 10, 8, 9, 5, 18, 17, 15, 16, 12, 13, 7, 29, 28, 26, 27, 23, 24, 18, 28, 20, 21, 11
Offset: 1

Views

Author

Omar E. Pol, Jun 30 2012

Keywords

Comments

Each part of a partition of n belongs to a different region of n. The "region number" of a part of the r-th region of n is equal to r. For the definition of "region of n" see A206437.

Examples

			For n = 5 we have:
------------------------------------------------------
.              Two arrangements             Sum of
k           of the partitions of 5        partition k
------------------------------------------------------
7      [5]                          [5]        5
6      [3+2]                      [3+2]        5
5      [4+1]                    [4  +1]        5
4      [2+1+1]                [2+2  +1]        5
3      [3+1+1]              [3  +1  +1]        5
2      [2+1+1+1]          [2+1  +1  +1]        5
1      [1+1+1+1+1]      [1+1+1  +1  +1]        5
------------------------------------------------------
.              Two arrangements
.           of the region numbers           Sum of
k           of the partitions of 5          zone k
------------------------------------------------------
7      [7]                          [7]        7
6      [6,7]                      [6,7]       13
5      [5,7]                    [5,  7]       12
4      [4,5,7]                [4,5,  7]       16
3      [3,5,7]              [3,  5,  7]       15
2      [2,3,5,7]          [2,3,  5,  7]       17
1      [1,2,3,5,7]      [1,2,3,  5,  7]       18
------------------------------------------------------
So row 5 of triangle gives: 18, 17, 15, 16, 12, 13, 7.
.
Triangle begins:
1;
3,2;
6,5,3;
11,10,8,9,5;
18,17,15,16,12,13,7;
29,28,26,27,23,24,18,28,20,21,11;
		

Crossrefs

Column 1 is A026905. Right border = row lengths = A000041, n>=1. Row sums give A210972.

A210972 Sum of all region numbers of all parts of all partitions of n.

Original entry on oeis.org

1, 5, 14, 43, 98, 255, 532, 1201, 2413, 4968, 9427, 18475
Offset: 1

Views

Author

Omar E. Pol, Jun 30 2012

Keywords

Comments

Each part of a partition of n belongs to a different region of n. The "region number" of a part of the r-th region of n is equal to r. For the definition of "region of n" see A206437.

Examples

			For n = 5 we have:
---------------------------------------------------
.              Two arrangements
k           of the partitions of 5
---------------------------------------------------
7      [5]                          [5]
6      [3+2]                      [3+2]
5      [4+1]                    [4  +1]
4      [2+1+1]                [2+2  +1]
3      [3+1+1]              [3  +1  +1]
2      [2+1+1+1]          [2+1  +1  +1]
1      [1+1+1+1+1]      [1+1+1  +1  +1]
---------------------------------------------------
.              Two arrangements
.           of the region numbers           Sum of
k           of the partitions of 5          zone k
---------------------------------------------------
7      [7]                          [7]        7
6      [6,7]                      [6,7]       13
5      [5,7]                    [5,  7]       12
4      [4,5,7]                [4,5,  7]       16
3      [3,5,7]              [3,  5,  7]       15
2      [2,3,5,7]          [2,3,  5,  7]       17
1      [1,2,3,5,7]      [1,2,3,  5,  7]       18
---------------------------------------------------
The total sum is a(5) = 1+2^2+3^2+4+5^2+6+7^2 = 1+4+9+4+25+6+49 = 18+17+15+16+12+13+7 = 98.
		

Crossrefs

Partial sums of A210969. Row sums of triangle A210971.

A210966 Sum of all region numbers of all parts of the n-th region of the shell model of partitions.

Original entry on oeis.org

1, 4, 9, 4, 25, 6, 49, 8, 18, 10, 121, 12, 26, 14, 225, 16, 34, 18, 76, 20, 21, 484, 23, 48, 25, 104, 27, 56, 29, 900, 31, 64, 33, 136, 35, 36, 259, 38, 78, 40, 41, 1764, 43, 88, 45, 184, 47, 96, 49, 400, 51, 52, 159, 54, 55, 3136, 57, 116, 59, 240
Offset: 1

Views

Author

Omar E. Pol, Jul 01 2012

Keywords

Comments

Each part of a partition of n belongs to a different region of n. The "region number" of a part of the r-th region of n is equal to r. For the definition of "region of n" see A206437.

Examples

			The first seven regions of the shell model of partitions (or the seven regions of 5) are [1], [2, 1], [3, 1, 1], [2], [4, 2, 1, 1, 1], [3], [5, 2, 1, 1, 1, 1, 1] therefore the "region numbers" are [1], [2, 2], [3, 3, 3], [4], [5, 5, 5, 5, 5], [6], [7, 7, 7, 7, 7, 7, 7]. So a(1)..a(7) give: 1, 4, 9, 4, 25, 6, 49.
Also written as an irregular triangle the sequence begins:
1;
4;
9;
4,25;
6,49;
8,18,10,121;
12,26,14,225;
16,34,18,76,20,21,484;
23,48,25,104,27,56,29,900;
31,64,33,136,35,36,259,38,78,40,41,1764;
43,88,45,184,47,96,49,400,51,52,159,54,55,3136;
		

Crossrefs

Row n has length A187219(n). Row sums give A210969. Right border gives A001255, n >= 1.

Formula

a(n) = n*A194446(n).
Showing 1-3 of 3 results.