Sum of squares of hexanacci numbers (A001592, Fibonacci 6-step numbers).

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =1a(6) =2a(7) =6a(8) =22a(9) =86a(10) =342a(11) =1366a(12) =5335a(13) =20960a(14) =82464a(15) =324528a(16) =1277104a(17) =5025200a(18) =19770800a(19) =77789489a(20) =306071370a(21) =1204272270a(22) =4738336974a(23) =18643463374a(24) =73354544590a(25) =288620849614