Sum of the areas of the first n Jacobsthal rectangles.

Terms

a(0) =0a(1) =1a(2) =4a(3) =19a(4) =74a(5) =305a(6) =1208a(7) =4863a(8) =19398a(9) =77709a(10) =310612a(11) =1242907a(12) =4970722a(13) =19884713a(14) =79535216a(15) =318148151a(16) =1272578046a(17) =5090341317a(18) =20361307020a(19) =81445344595a(20) =325781145370