x(n):=sum(x[i],i,1,n)$

f(x):=3;

f12345689(x):=3;

f12345689012345689012345689012345689012345689012345689012345689012345689012345689012345689(x):=3;

f(x):=x(50);

f12345689(x):=x(50);

f12345689012345689012345689012345689012345689012345689012345689012345689012345689012345689(x):=x(50);