Help for a generic formula for a stellar pattern.?

We were given a 6-stellar number and each next time in the pattern it is increasing by an increment of 12. for example, S2 = 12, S3 = S2 + 24, S4 = S3+ 36. S1 = 1 dot (the center vertice and all the patterns have that but I exempted them from the example). I have so far come up with the generic formula Sn = [(S_(n-1)) + 12(n-1)] + 1, but I need to come up with a generic formula to find any nth term, for instance the 100th term would require me to find the 99th term and so forth, so I need to come up with one that would replace the S_(n-1) with something else. I noticed that the next pattern in the series is increasing increments of 12 (S2 = 0, S3 = 12, S4= 36, S5 = 72 for the S_(n-1) term.) which is 12(1), 12(3), 12(6), 12(10),...Which is adding +2,+3,+4 to every timed increment. I cannot figure out the pattern still, could someone help me to find the generic formula?