@Preben Alsholm thank you :)

@Preben Alsholm it is very nice, thank you. It is usable for this and similar problems, but.. But is there an option, to do it in steps(like I have indicated)? I´ll solve more ODE and FDE, so I´m not sure, that a system of ODE will be enough. For now, it´s just a something for interest, in the future may be not.

I have one more stupid question. What is a large number of n (or dimension of system) for solving mentioned equation in maple? I mean how many steps is possible to do in this metod using todays PC.

@Preben Alsholm

@Preben Alsholm that would work, while there only two ODE. Bud this is only a part of my problem. A want to take first solution to second ODE, second solution do third ODE, atc. many times.

@Markiyan Hirnyk I tried what you mentioned above.But always comes error "kernel connection has been lost". In my opinion, the problem is that maple doesn´t compute particular solution, but only remeber a procedure how to do it. So when it is wrapped more these problems together, it is not possible to compute it at once at the end. I think it is nessesery to compute after every each step.

@Preben Alsholm looks easy and works. Thank you once more :)

@tomleslie 

much better, thank you for your reply. I´m not going to go through whole function, only a special part. I´ll be working and may be have more questions.Thanks