OFFSET
0,2
EXAMPLE
For n = 6 the illustration of the three views of a three-dimensional version of the shell model of partitions with 6 shells looks like this:
.
.
. 6 6
. 3 3 3 3
. 4 2 4 2
. 2 2 2 2 2 2
. 5 1 5 1
. 3 2 1 3 2 1
. 4 1 1 4 1 1
. 2 2 1 1 2 2 1 1
. 3 1 1 1 3 1 1 1
. 2 1 1 1 1 2 1 1 1 1
. 1 1 1 1 1 1 1 1 1 1 1 1
.
.
. 1 2 5 9 12 6 \
. 1 1 3 5 6 \
. 1 1 2 4 \ 6th slice of
. 1 1 2 / tetrahedron A210961
. 1 1 /
. 1 /
.
. A000217(6) = 21
.
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Apr 22 2012
STATUS
approved