There is a technique for solving your sequence. First write down
the sequence, then find the difference between each number in the
series. After you have discovered a constant number (in your case,
the constant is 1), it will determine the degree of power for your
sequence.
the most brainless method, as pointed out by mike, is by using
(1/2)(n+1)(n+2)
if you generate from n=0, you get,
1,3,6,10,15...
you see in between, +2, +3, +4, +5
from there, you can find out many things... :)
There are other equally brainless methods as well, but sad to
say, my compiled list from sec sch has been lost by one of my
previous students when I just started out teaching... sigh....
