1,2,6,42,1806,.... = ?

1,2,6,42,1806,.... = ?

Theres a Logic behind that, but its very simple.

Consider the number as a, then the next number would be a *( a + 1). In the same manner 

1* (1 + 1) = 2;  2*(2 + 1)= 6; 6 * (6 + 1)= 42; 42 * (42 + 1)= 1806; 

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1806 * (1806 + 1 )= 3263442. Simple isn't it.