Exponential self-convolution of Pell numbers.

Terms

a(0) =0a(1) =0a(2) =2a(3) =12a(4) =64a(5) =320a(6) =1568a(7) =7616a(8) =36864a(9) =178176a(10) =860672a(11) =4156416a(12) =20070400a(13) =96911360a(14) =467935232a(15) =2259402752a(16) =10909384704a(17) =52675215360a(18) =254338531328