Tetranacci numbers A073817 without the leading term 4.

Terms

a(0) =1a(1) =3a(2) =7a(3) =15a(4) =26a(5) =51a(6) =99a(7) =191a(8) =367a(9) =708a(10) =1365a(11) =2631a(12) =5071a(13) =9775a(14) =18842a(15) =36319a(16) =70007a(17) =134943a(18) =260111a(19) =501380a(20) =966441a(21) =1862875a(22) =3590807a(23) =6921503a(24) =13341626a(25) =25716811a(26) =49570747a(27) =95550687a(28) =184179871a(29) =355018116