Tetranacci numbers starting with first four squares.

Terms

a(0) =1a(1) =4a(2) =9a(3) =16a(4) =30a(5) =59a(6) =114a(7) =219a(8) =422a(9) =814a(10) =1569a(11) =3024a(12) =5829a(13) =11236a(14) =21658a(15) =41747a(16) =80470a(17) =155111a(18) =298986a(19) =576314a(20) =1110881a(21) =2141292a(22) =4127473a(23) =7955960a(24) =15335606a(25) =29560331a(26) =56979370a(27) =109831267a(28) =211706574a(29) =408077542