Membuat program untuk mencetak deret aritmatika [PASCAL]

program aritmatika;
uses crt;
var
s,a,n,b,un : integer;
begin
clrscr;
writeln('deret aritmatika');
a := 3;
b := 4;
for n := 1 to 10 do
begin
un := a+(n-1)*b;
write(un,',');
s := un + un;
end;
writeln;
writeln('jumlah deret aritmatika = ',s);
readln;
end.