User blog:VoidSansXD/Guess the pattern of this function owo

$_0 = 0.4

$_1 = 400

$_2 = 412

$_3 = 484

$_4 = 488

$_5 = 549 (548.92 to be exact)

$_6 = 549

$_7 = 549.08

$_8 = 564

$_9 = 1040

$_10 = 1060

$_11 = 1324

$_12 = 2,000

$_13 = 4,000

$_14 = 8,000

$_15 = 20,000

$_16 = 40,000

$_17 = 200,000

$_18 = 400,000

$_19 = 2,000,000

$_20 = 4,000,000

$_21 = 40,000,000

sry for being gone for so long lol