MathDB
Putnam 1995 B3

Source:

July 1, 2014
Putnamlinear algebramatrixfunctioncollege contests

Problem Statement

To each number with n2n^2 digits, we associate the n×nn\times n determinant of the matrix obtained by writing the digits of the number in order along the rows. For example : 8617det(  86    17  )=508617\mapsto \det \left(\begin{matrix}{\;8}& 6\;\\ \;1 &{ 7\;}\end{matrix}\right)=50. Find, as a function of nn, the sum of all the determinants associated with n2n^2-digit integers. (Leading digits are assumed to be nonzero; for example, for n=2n = 2, there are 90009000 determinants.)