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.

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A182993 Number of parts of the n-th subshell of the head of the last section of the set of partitions of any odd integer >= 2n+1.

Original entry on oeis.org

1, 2, 5, 12, 21, 39, 73, 118, 198, 326, 510, 797, 1234, 1854, 2778, 4122, 6014, 8717, 12550, 17849, 25252, 35486, 49447, 68540, 94480, 129378, 176339, 239165, 322676, 433487, 579907, 772318, 1024691, 1354445, 1783504
Offset: 1

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Author

Omar E. Pol, Feb 06 2011

Keywords

Comments

The last section of the set of partitions of 2n+1 contains n subshells.
Also first differences of A182735. - Omar E. Pol, Mar 03 2011

Examples

			a(5)=21 because the 5th subshell of the head of the last section of any odd integer >= 11 looks like this:
(11 . . . . . . . . . . )
( 6 . . . . . 5 . . . . )
( 7 . . . . . . 4 . . . )
( 8 . . . . . . . 3 . . )
( 4 . . . 4 . . . 3 . . )
( 5 . . . . 3 . . 3 . . )
.                  (2 . )
.                  (2 . )
.                  (2 . )
.                  (2 . )
.                  (2 . )
.                  (2 . )
.                  (2 . )
.                  (2 . )
The subshell has 21 parts, so a(5)=21.
		

Crossrefs

Formula

a(n) = A138135(2n+1) - A138135(2n-1).

Extensions

More terms from Omar E. Pol, Mar 03 2011

A182813 Triangle read by rows in which row n lists the parts of the largest subshell of all partitions of 2n+1 that do not contain 1 as a part.

Original entry on oeis.org

3, 5, 2, 7, 4, 3, 2, 2, 9, 5, 4, 6, 3, 3, 3, 3, 2, 2, 2, 2, 11, 6, 5, 7, 4, 8, 3, 4, 4, 3, 5, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 13, 7, 6, 8, 5, 9, 4, 5, 4, 4, 10, 3, 5, 5, 3, 6, 4, 3, 7, 3, 3, 4, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2
Offset: 1

Views

Author

Omar E. Pol, Dec 04 2010

Keywords

Comments

In the shell model of partitions the head of the last section of the set of partitions of 2n+1 contains n subshells.
The first n rows of this triangle represent these subsells.
This sequence contains the same elements of A182743 but in distinct order.
See A135010 and A138121 for more information.

Examples

			For n=1 the unique partition of 2n+1=3 that does not contains 1 as part is 3, so row 1 has an element = 3.
For n=2 there are 2 partitions of 2n+1=5 that do not contain 1 as part:
5 ............ or ....... 5 . . . .
3 + 2 ........ or .......(3). . 2 .
These partitions contain (3), the row n-1 of triangle, so
the parts of the largest subshell are 5, 2.
For n=3 there are 4 partitions of 2n+1=7 that do not contain 1 as part:
7 ............ or ....... 7 . . . . . .
4 + 3 ........ or ....... 4 . . . 3 . .
5 + 2 ........ or .......(5). . . . 2 .
3 + 2 + 2 .... or .......(3). .(2). 2 .
These partitions contain (5) and (3),(2), the parts of the rows < n of triangle, so the parts of the largest subshell are 7, 4, 3, 2, 2.
And so on.
Triangle begins:
3,
5,2,
7,4,3,2,2,
9,5,4,6,3,3,3,3,2,2,2,2,
11,6,5,7,4,8,3,4,4,3,5,3,3,2,2,2,2,2,2,2,2,
		

Crossrefs

Showing 1-2 of 2 results.