Question

Maths please help u thingy

Answer 1

$\begin{array}{cll} term&\stackrel{u_n+u_{n-1}+1}{value}\\ \cline{1-2} u_1&1\\ u_2&3\\ u_3&\stackrel{u_n}{3}+\stackrel{u_{n-1}}{1}+1\\ &5\\ u_4&\stackrel{u_n}{5}+\stackrel{u_{n-1}}{3}+1\\ &9\\ u_5&\stackrel{u_n}{9}+\stackrel{u_{n-1}}{5}+1\\ &15 \end{array}$

in recursive sequence notation, is another way of saying
"the next term will be the current one plus the one before it, plus one"