Fibonacci sequence beginning 0, 21.

Terms

a(0) =0a(1) =21a(2) =21a(3) =42a(4) =63a(5) =105a(6) =168a(7) =273a(8) =441a(9) =714a(10) =1155a(11) =1869a(12) =3024a(13) =4893a(14) =7917a(15) =12810a(16) =20727a(17) =33537a(18) =54264a(19) =87801a(20) =142065a(21) =229866a(22) =371931a(23) =601797a(24) =973728a(25) =1575525a(26) =2549253a(27) =4124778a(28) =6674031a(29) =10798809