Question

2,7,26,101,400 what is the next number

Answer 1

$a_1=2\\a_2=4*a_1-1=4*2-1=7\\a_3=4*a_2-2=4*7-2=26\\a_4=4*a_3-3=4*26-3=101\\a_5=4*a_4-4=4*101-4=400\\a_6=4*a_5-5=4*400-5=1595$