MathDB
{a_n} sequence

Source:

October 15, 2005

Problem Statement

If the sequence {an}\{a_n\} is defined by \begin{align*}a_1 &= 2,\\ a_{n+1} &= a_n + 2n\qquad (n\geq 1),\end{align*} then a100a_{100} equals
<spanclass=latexbold>(A)</span>9900<spanclass=latexbold>(B)</span>9902<spanclass=latexbold>(C)</span>9904<spanclass=latexbold>(D)</span>10100<spanclass=latexbold>(E)</span>10102<span class='latex-bold'>(A) </span>9900\qquad <span class='latex-bold'>(B) </span>9902\qquad <span class='latex-bold'>(C) </span>9904\qquad <span class='latex-bold'>(D) </span>10100\qquad <span class='latex-bold'>(E) </span>10102