When analyzing the sequence, you will realize the rule for the sequence is: Un=Un−1+3+n Where n≥2 When n=2 U2=U2−1+3+2 U2=U1+5 U1=11 U2=11+5=16 When n=3 U3=U3−1+3+3 U3=U2+6 U2=16 U3=16+6=22 When n=4 U4=U4−1+3+4 U4=U3+7 U3=22 U4=22+7=29 When n=5 U5=U5−1+3+5 U5=U4+8 U4=29 U5=29+8=37 When n=6 U6=U6−1+3+6 U6=U5+9 U5=37 U6=37+9=46 When n=7 U7=U7−1+3+7 U7=U6+10 U6=46 U7=46+10=56