MathDB
Putnam 1985 A3

Source:

August 5, 2019
Putnam

Problem Statement

Let dd be a real number. For each integer m0,m \geq 0, define a sequence {am(j)},j=0,1,2,\left\{a_{m}(j)\right\}, j=0,1,2, \ldots by the condition \begin{align*} a_{m}(0)&=d / 2^{m},\\ a_{m}(j+1)&=\left(a_{m}(j)\right)^{2}+2 a_{m}(j),   j \geq 0. \end{align*} Evaluate limnan(n).\lim _{n \rightarrow \infty} a_{n}(n).