How many ways are there to pick an ordered tuple of 5 elements from the set of positive integers between 1 and 50 inclusive, provided that there must be at least one consecutive sequence of 4 consecutive elements?

Valid tuples: (1, 47, 48, 49, 50), (6, 6, 7, 8,9), (9, 10, 11, 12, 13), (45, 6, 7, 8, 9).

Invalid tuples: (1, 11, 2, 3, 4), (43, 42, 41, 40, 9), (5, 5, 5, 5, 5)

Hint: Inclusion-Exclusion. Try counting the number of sequences with 5 consecutive elements