A={1+1(-n)2/n E n} Determine all elements

Question

Determine all elements

A={1+1(-n)2/ n E n}

Answer 1

The defining expression needs clarification.  is it 1 + (1/n)(n)²?

 

Did you mean n ∈ N, i.e n is any Natural Number?

Okay, if you accept my rewrite of the expression, where I killed the - sign in front of of the parenthesized n, because it dies when the quantity is squared, AND the part "/nEn" was not intended as division, but meant that n is an element of the natural number set N, THEN... a(1) = 2, a(2) = 5, a(3) = 10, a(4) = 17, a(5) = 26, etc. Note that there's no division in the definition of a(n)'s. Note also that the set of constant differences between any element and its predecessor is the set of odd positive integers beginning with 3 ; this is characteristic of discrete quadratic functions.