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A206441
Triangle read by rows. T(n,k) = number of distinct parts in the k-th region of the last section of the set of partitions of n.
0
1, 2, 2, 1, 3, 1, 3, 1, 2, 1, 4, 1, 2, 1, 4, 1, 2, 1, 3, 1, 1, 5, 1, 2, 1, 3, 1, 2, 1, 5, 1, 2, 1, 3, 1, 1, 4, 1, 2, 1, 1, 6
OFFSET
1,2
COMMENTS
a(n) is also the number of distinct parts in the n-th region of the shell model of partitions (see A135010 and A206437).
EXAMPLE
The first region in the last section of the set of partitions of 6 looks like this:
. **
There is only one part, so T(6,1) = 1.
The second region in the last section of the set of partitions of 6 looks like this:
. ****
. **
There are two distinct parts, so T(6,2) = 2.
The third region in the last section of the set of partitions of 6 looks like this:
. ***
There is only one part, so T(6,3) = 1.
The 4th region in the last section of the set of partitions of 6 looks like this:
. ******
. ***
. **
. **
. *
. *
. *
. *
. *
. *
. *
There are four distinct parts, so T(6,4) = 4.
Written as a triangle:
1;
2;
2;
1, 3;
1, 3;
1, 2, 1, 4;
1, 2, 1, 4;
1, 2, 1, 3, 1, 1, 5;
1, 2, 1, 3, 1, 2, 1, 5;
1, 2, 1, 3, 1, 1, 4, 1, 2, 1, 1, 6;
CROSSREFS
KEYWORD
nonn,tabf,more
AUTHOR
Omar E. Pol, Feb 13 2012
STATUS
approved