⎩ ⎪ ⎪ ⎨ ⎪ ⎪ ⎧ ​ a(1)=−13 a(n)=a(n−1)+4 ​ Find the 2nd2^{\text{nd}} 2 nd 2, start superscript, start text, n, d, end text, end superscript term in the sequence