function [a,b,c,s] = rk6()
    % Runge-Kutta 6 from Alshina07 
    s = 7;
    a = sparse(s,s-1);
    a(2,1) = 4/7; 
    a(3,1) = 115/112; a(3,2) = -5/16;
    a(4,1) = 589/630; a(4,2) = 5/18; a(4,3) = -16/45;
    a(5,1) = 229/1200 - 29/6000*sqrt(5); a(5,2) = 119/240 - 187/1200*sqrt(5); a(5,3) = -14/75 + 34/375*sqrt(5); a(5,4) = -3/100*sqrt(5);
    a(6,1) = 71/2400 - 587/12000*sqrt(5); a(6,2) = 187/480 - 391/2400*sqrt(5); a(6,3) = -38/75 + 26/375*sqrt(5); a(6,4) = 27/80 - 3/400*sqrt(5); a(6,5) = (1+sqrt(5))/4;
    a(7,1) = -49/480 + 43/160*sqrt(5); a(7,2) = -425/96 + 51/32*sqrt(5); a(7,3) = 52/15 - 4/5*sqrt(5); a(7,4) = -27/16 + 3/16*sqrt(5); a(7,5) = 5/4 - 3/4*sqrt(5); a(7,6) = 5/2 - 1/2*sqrt(5);
    b = [1/12; 0; 0; 0; 5/12; 5/12; 1/12];
    c = [0; 4/7; 5/7; 6/7; (5-sqrt(5))/10; (5+sqrt(5))/10; 1];
end