4 years ago

Fill in the missing number: 2, 8, 27, 85, 260, _, 2365

Mathematics

1 answer:

nexus9112 [7]4 years ago

6 0

Each number is mutliplied by 3 and then numbers 2,3,4,5,... are added successively.

2*3+2=8

8*3+3=27

27*3+4=85

85*3+5=260

260*3+6=786

So it's 786.

Btw, the general formula for this sequence is $a_n=\dfrac{1}{12}(-6n+13\cdot3^n-9)$

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