(2n) 2n+1 yn+(-2+3)(-(+2(+4)(+2x (2n+1)!( ) 2 ( )( )( )( ) 5 1 - 3 -1 2 4 -1 5! l l l l c c + + = 2n c = ( ) ( )( ) ( )( ) ( ) ( ) ( ) 0 - 2 2 - 2 4 ... 1 3 ... 2 -1 -1 4 2 ! n l n l n l l l l n c n + + + + + 2n+1 c = ( ) ( )( ) ( )( )( ) ( ) ( ) 1 ( ) - 2 1 - 2 3 ... -1 2 4 ... 2 -1 5 2 1 ! n l n l n l l l l n c n + + + + + +