P is a positive integer such that each of sod(P-1), sod(P) and P+1 is divisible by 13. Determine the minimum value of P.
What if each of P-1, sod(P) and sod(P+1) is divisible by 13? How about each of sod(P-1), P and sod(P+1) being divisible by 13?
What will be the respective answers to Part A, when the words "divisible by 13" are replaced with "divisible by 11"?
*** sod(x) refers to the sum of the digits in the base ten expansion of x.