Question

帮忙找规律3,6,10,21请问这个数列满足什么规律

Answer 1

a(n) = (( n - 5.5 ) * n + 12.5 )* n - 5

a(1)=3

a(2)=6

a(3)=10

a(4)=21

a(5)=45

a(6)=88

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