Sum of squares of tetranacci numbers (A001630).

Terms

a(0) =0a(1) =0a(2) =1a(3) =5a(4) =14a(5) =50a(6) =194a(7) =723a(8) =2659a(9) =9884a(10) =36780a(11) =136636a(12) =507517a(13) =1885793a(14) =7006962a(15) =26034006a(16) =96728470a(17) =359395319a(18) =1335332919a(19) =4961420008a(20) =18434129192a(21) =68491926888a(22) =254481427113a(23) =945524491213