@acer  I figured it out just like you, but maybe OP just confuses these interfaces.

@mapleatha  Acer's method and old reference worked for me also (only in  Standard worksheet rather than Classic worksheet).

@Carl Love   Thank you for the detection of serious gap in my decision.

@nMaple  Select  remember table assignment  and press  OK

@Markiyan Hirnyk  For  n=4  Maple 2015 works incorrectly. Here is the calculation in Maple 16 with visualization:

restart;

P := combinat[choose]({$1 .. 4}, 2):

S := combinat[powerset](P):

L := [seq(GraphTheory[Graph](4, S[k]), k = 1 .. nops(S))]:

M := [ListTools[Categorize]((x, y)-> GraphTheory[IsIsomorphic](x, y), L)]:

K := [seq(M[i, 1], i = 1 .. nops(M))]:

nops(K);

plots[display](Matrix(3, 5, [seq(GraphTheory[DrawGraph](K[k]), k = 1 .. 11), plot([[0, 0]], axes = none)$4]), scaling = constrained);

@Markiyan Hirnyk   

See   http://oeis.org/search?q=1%2C1%2C2%2C4%2C11%2C34&sort=&language=english&go=Search

@Carl Love   Thank you, very elegant improvement. 

@Carl Love  I corrected and expanded my post.

@kegj  Should be  plot1  rather than  plot 1 . Copy my code and simply paste it into your document and run.

@kegj  You have forgotten to call  plots  package. I also removed the square brackets in  filled=[true,color=blue] . In older versions it causes an error, in the new versions can leave brackets.

y:=x->sin(x):

a:= -1:

b:=6:

plot1:=plot(sin(x), x=-1..6,color=red,title="graph of sin(x)"):      

plot2:=plot(sin(x),x=1..5,filled=true,color=blue):   

plots[display](plot1,plot2,view=[-1..6,-1..1],title="graph of sin(x)");

@nMaple  All is almost the same;

plot3d(x*y, x = 0 .. 2, y = x^2 .. 2*x, style = surface, filled = true, axes = normal, view = [-0.9 .. 2.4, -0.9 .. 4.4, 0 .. 8.4], orientation = [-67, 70]);

The proportions of the body in the drawing violated. This body is very narrow and high. Therefore, for a better understanding of its structure, I did not use the  scaling=constrained  option.

@nMaple   Add  style=surface  option and use  user lighting:

plot3d(x^2-y^2+4, x = -1 .. 1, y = 0 .. 2, style=surface, filled = true, axes = normal, view = [-1.4 .. 1.4, 0 .. 2.4, 0 .. 5.4], scaling = constrained, orientation = [50, 70]);

@nMaple  For different bodies color schemes may be different.

@Carl Love   Yes, you're right! I considered all my examples in classic worksheet Maple 2015. Check all in Maple 12. In fact there `+` command is significally faster than add command.

@Carl Love  You wrote  " I think that `+`(U[]) is faster than add(u, u= U)".  But the following examples with direct computation the sum of large number of terms does not confirm this conclusion.

The first 2 examples with the precomputed list:

restart;

X:=[seq(i^3, i=1..5000000)]:

t:=time():

`+`(X[]);

time()-t;

                            156250062500006250000000000

                                               9.453

restart;

X:=[seq(i^3, i=1..5000000)]:

t:=time():

add(x, x=X);

time()-t;

                             156250062500006250000000000

                                                7.797

In addition 2 examples without the precomputed list:

restart;

t:=time():

add(i^3, i=1..5000000);

time()-t;

                             156250062500006250000000000

                                                1.953

restart;

t:=time():

`+`(seq(i^3, i=1..5000000));

time()-t;

                             156250062500006250000000000

                                                18.032