Not sure how to crack a chained SHA-256 hash
I've got a chain of hashes where each one is put through SHA-256 to produce the next, but I need a way to work out a hash earlier in the chain via brute-force. How would I set this up with hashcat?

If my problem is unclear, imagine my hasher takes a number, triples it, then applies modulo 50. If I start with 12, I get:
12, 36, 8, 24, 22, 16, 48
I need a way of working out that 8 came before 24, but it doesn't need to be 8 specifically. It can be 108, it will still work fine for what I need. Ideally, it should be able to state what was a few back (that 12 was 4 before 22).
there's no way to do that with the existing kernels, but since we went OSS you can hack one of them to do what you like. I'd recommend kernel source of -m 1400 as a template