Convolution of Jacobsthal numbers and Pell numbers.

Terms

a(0) =0a(1) =0a(2) =1a(3) =3a(4) =10a(5) =28a(6) =77a(7) =203a(8) =526a(9) =1340a(10) =3377a(11) =8435a(12) =20930a(13) =51660a(14) =126981a(15) =311083a(16) =760070a(17) =1853068a(18) =4509897a(19) =10960243a(20) =26605146a(21) =64520060a(22) =156344317a(23) =378606795a(24) =916354110a(25) =2216907420a(26) =5361353761a(27) =12961984563a(28) =31330062130a(29) =75711587308