MathDB
0742

Source:

May 26, 2008
analytic geometrygraphing linessloperotationgeometrygeometric transformationreflection

Problem Statement

Find the number of finite sequences \{a_1,a_2,\ldots,a_{2n\plus{}1}\}, formed with nonnegative integers, for which a_1\equal{}a_{2n\plus{}1}\equal{}0 and |a_k \minus{}a_{k\plus{}1}|\equal{}1, for all k{1,2,,2n} k\in\{1,2,\ldots,2n\}.