Question

What is multiplication of the sequence 1, 2, 3, 4,… by the sequence 1, 3, 5, 7, 11,….?

(a) 1, 5, 14, 30,…

(b) 2, 8, 16, 35,…

(c) 1, 4, 7, 9, 13,…

(d) 4, 8, 9, 14, 28,…

I got this question by my college director while I was bunking the class.

My question is based upon Discrete Probability in section Discrete Probability of Discrete Mathematics

Answer 1

The correct option is (a) 1, 5, 14, 30,…

To explain: The first constant term is 1⋅1, next term will be 1⋅3 + 2⋅1 = 5, the next term: 1⋅5 + 2⋅3 + 3⋅1 = 14, another one: 1⋅7 + 2⋅5 + 3⋅3 + 4⋅1 = 30. The resulting sequence is 1, 5, 14, 30,…