Squares of Jacobsthal numbers.

Terms

a(0) =0a(1) =1a(2) =1a(3) =9a(4) =25a(5) =121a(6) =441a(7) =1849a(8) =7225a(9) =29241a(10) =116281a(11) =466489a(12) =1863225a(13) =7458361a(14) =29822521a(15) =119311929a(16) =477204025a(17) =1908903481a(18) =7635439161a(19) =30542106169a(20) =122167725625a(21) =488672300601