A112459 - OEIS

A112459

Absolute value of coefficient of term [x^(n-3)] in characteristic polynomial of maximum matrix A of size n X n, where n >= 3. Maximum matrix A(i,j) is MAX(i,j), where indices i and j run from 1 to n.

%I #21 Dec 17 2017 07:58:17

%S 3,23,98,308,798,1806,3696,6996,12441,21021,34034,53144,80444,118524,

%T 170544,240312,332367,452067

%N Absolute value of coefficient of term [x^(n-3)] in characteristic polynomial of maximum matrix A of size n X n, where n >= 3. Maximum matrix A(i,j) is MAX(i,j), where indices i and j run from 1 to n.

%F a(n) = n*(n^2-4)*(n^2-1)*(5*n+3)/6!.

%F G.f.: x^3*(3+2*x)/(1-x)^7. - _Colin Barker_, Mar 28 2012

%o (Octave, MATLAB) for n=3:20 a = zeros(n); for i=1:n for j=1:n a(i,j) = max(i,j); end end b = poly(a); b(4) end

%Y Cf. A000217, A000914, A001844, A112460, A112461, A112462, A112463, A112464.

%K easy,nonn

%O 3,1

%A _Paul Max Payton_, Sep 23 2005

%E Offset changed from 1 to 3 and formulas adapted by _Bruno Berselli_, Mar 29 2012