Question

What is the next number in the serie 12, 77 252. 621

Answer 1

2*2+2=6

2*6+3=15

2*15+5=35

2*35+7=77

2*77+11=165

Hope you got your answer.

But wait … this is not perfect answer.

Answer is 143.

2*3 = 6

3*5 = 15

5*7 = 35

7*11 = 77

11*13 = 143 Here is your answer.

Multiplication of prime number’s. it’s perfect series.

Answer 2

The correct answer is 1292.

Given: The series = 12, 77, 252, 621.

To Find: Next term.

Solution:

12 = $(1^{2} +3)^{2} -4$ = 16-4

77 = $(2^{2} +5)^{2} -4=81-4$

252 = $(3^{2} +7)^{2} -4=255-4$

621 = $(4^{2} +9)^{2} -4=625-4$

Logic: Number = (square + odd number$)^{2}$ - 4.

Next term = $(5^{2} +11)^{2} -4=1296-4$

Hence, the next term is 1292.

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