Hey Isee! Nice work.
I'm still plugging on the an, bn, a(n-1), and b(n-1) records. Here's my WIP for c145 and c287. Lots of cool patterns, but no breakthrough as of yet.
Interesting find: for c145, the c value for b(n-1)=17400, and the c val for (bn) = 26245. When you subtract them, you get 8845, which is BigN * c = 61 * 145 = 8845
I tried it on c287 but the pattern didn't hold. Just wanted to share a cool find tho! :)
I'm gonna keep plugging and thinking. Anyone else got some work in progress??