This sequence has me stumped.... anyone have an idea on what the closed form is?
0, 1, 4, 12, 28, 55, 96, 154
Labelling $\displaystyle a_0, a_1, a_2, \ldots$ . Then $\displaystyle a_1$ is the first triangular number, $\displaystyle a_2$ is the second square number, $\displaystyle a_3$ is the third pentagonal number, etc...
I'm just working on a closed form but it shouldn't be too difficult at all.
Pomp
EDIT: $\displaystyle a_n = n \left( {}^nC_2 + 1 \right)$ works.