Interesting sequence - find closed form

**vexiked** · September 30th 2009, 07:40 AM

This sequence has me stumped.... anyone have an idea on what the closed form is?

0, 1, 4, 12, 28, 55, 96, 154

**CaptainBlack** · September 30th 2009, 08:00 AM

Originally Posted by vexiked

This sequence has me stumped.... anyone have an idea on what the closed form is?

0, 1, 4, 12, 28, 55, 96, 154

I'm not surprised, see this

CB

**TravisH82** · September 30th 2009, 08:11 AM

Originally Posted by CaptainBlack

I'm not surprised, see this

CB

Whoa! awesome resource. CaptainBlack, can you point me to a sticky with useful links such as that? I've been searching around with the google, but come up with too much random junk.

Thanks!

**pomp** · September 30th 2009, 08:38 AM

Originally Posted by vexiked

This sequence has me stumped.... anyone have an idea on what the closed form is?

0, 1, 4, 12, 28, 55, 96, 154

Labelling $a_0, a_1, a_2, \ldots$ . Then $a_1$ is the first triangular number, $a_2$ is the second square number, $a_3$ 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: $a_n = n \left( {}^nC_2 + 1 \right)$ works.

Thread: Interesting sequence - find closed form

LinkBack

Thread Tools

Display

Interesting sequence - find closed form

Similar Math Help Forum Discussions

closed form for sequence z=z^2+c & generating function

Closed form for a sequence

closed form sequence

Writing a sequence in closed form

Geometric Sequence, find a closed form.

Search Tags