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number_sequence

Language/Type: Python recursion

Write a recursive function named number_sequence that accepts an integer n as a parameter and prints a sequence of n integers, descending from n to 1 and then ascending back from 1 to n as in the table below:

Call Output
number_sequence(1) 1
number_sequence(2) 1 1
number_sequence(3) 2 1 2
number_sequence(4) 2 1 1 2
number_sequence(5) 3 2 1 2 3
number_sequence(6) 3 2 1 1 2 3
number_sequence(7) 4 3 2 1 2 3 4
number_sequence(8) 4 3 2 1 1 2 3 4
number_sequence(9) 5 4 3 2 1 2 3 4 5
number_sequence(10) 5 4 3 2 1 1 2 3 4 5

Notice that for odd numbers the sequence has a single 1 in the middle while for even values it has two 1s in the middle.

Your function should raise a ValueError if passed a value less than 1.

Function: Write a Python function as described, not a complete program.

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