login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A176724
Triangle for number of partitions which define multiset repetition classes.
4
1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 2, 1, 1, 1, 0, 0, 0, 1, 0, 1, 2, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 2, 1, 1, 1, 0, 0, 0, 0, 0, 2, 1, 2, 2, 1, 1, 1, 0, 0, 0, 0, 0, 1, 2, 1, 2, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 2, 1, 2, 2, 1, 1, 1
OFFSET
1,42
COMMENTS
For definitions, references, links and examples see the corresponding partition array A176723.
Row sums coincide with those of array A176723 for n>=1, and they are given by A007294.
If for n=0 a 1 is added (the empty partition defines the empty multiset class) the tabl structure will be lost.
FORMULA
a(n,m) is the number of m part partitions of n which define m-multiset repetition classes. Multiset repetition class defining is equivalent to the following constraint on the exponents of a partition (1^e[1],2^e[2],...,M^e[M]):
e[1] >= e[2]>=...>=e[M]>=1, i.e., positive nonincreasing with largest part M. This will satisfy T(M) <= n where T(M) = A000217(M) are the triangular numbers; for each n every sufficiently small positive M does occur.
EXAMPLE
1;
0,1;
0,1,1;
0,0,1,1;
0,0,0,1,1;
0,0,1,1,1,1;
0,0,0,1,1,1,1;
...
CROSSREFS
a(7,5)=1 because there is only one 5 part partition of 7 which is 5-multiset repetition class defining, namely (1^3,2^2) (see row n=7 of the partition array A176723). This defines the 5-multiset class representative {1,1,1,2,2}.
Sequence in context: A321929 A089198 A059607 * A015318 A026836 A089052
KEYWORD
nonn,easy,tabl
AUTHOR
Wolfdieter Lang, Jul 14 2010
EXTENSIONS
Edited (in response to comments by Franklin T. Adams-Watters) by Wolfdieter Lang, Apr 02 2011
STATUS
approved