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.

A220484 Triangle read by rows: T(j,k) is the total number of appearances of the smallest parts in the j-th partition of n, with partitions as nonincreasing lists of parts in lexicographic order.

Original entry on oeis.org

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

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Author

Omar E. Pol, Jan 20 2013

Keywords

Comments

The sum of row n equals spt(n) = A092269(n), the smallest part partition function.

Examples

			For n = 5:
------------------------------------------
.                         number of
Partitions of 5         smallest parts
------------------------------------------
1 + 1 + 1 + 1 + 1              5
2 + 1 + 1 + 1                  3
3 + 1 + 1                      2
2 + 2 + 1                      1
4 + 1                          1
3 + 2                          1
5                              1
------------------------------------------
So row 5 is [5, 3, 2, 1, 1, 1, 1]. The sum of row 5 is 5+3+2+1+1+1+1 = spt(5) = A092269(n) = 14.
.
Written as an irregular triangle begins:
1;
2,1;
3,1,1;
4,2,1,2,1;
5,3,2,1,1,1,1;
6,4,3,2,2,1,1,3,1,2,1;
7,5,4,3,3,2,2,1,1,1,1,2,1,1,1;
8,6,5,4,4,3,3,2,2,2,2,1,1,1,1,4,2,1,1,1,2,1;
9,7,6,5,5,4,4,3,3,3,3,2,2,2,2,1,1,1,1,1,1,1,3,2,1,1,3,1,1,1;
		

Crossrefs

Column 1 is A000027. Row n has length A000041(n). Row sums give A092269.