find the missing number in sequence 1,2,3,6,11,20,...., 68?? a. 37 b.38 c. 40 d. 42 e. 44

u1 = 1
u2 = 2
u3 = 3
u4 = 6
u5 = 11
u6 = 20
u7 = ..
u8 = 68

mulai dari u1 = 1
u2 = u1+u1+u0=2
u3 = u1+u2+u0=3
u4 = u1+u2+u3 = 1+2+3 = 6
u5 = u3+u4+u2 = 11
u6 = u5+u4+u3 = 11+6+3 = 20
maka u7 = u6+u5+u4 =20+11+6 = 37 (A)