Cleaned up syntax in checkPrimes.
Optimized concatenablePrimes, doing work on smaller and smaller lists.
No need to find minimum, as it's in head.
Use primes below 10000, not first 10000 primes.
Removed obsolete comment from 60.
Simplified findMatchingNumbers in 61.
Working 61.
Removed primed definitions of figurate numbers.
Refactored checking for cycle to a separate function.
Removed findMatchingNumbers, isCyclic looks nicer.
Small cleanup in 61.