A Fielder sequence.

Terms

a(0) =1a(1) =3a(2) =7a(3) =11a(4) =26a(5) =45a(6) =85a(7) =163a(8) =304a(9) =578a(10) =1090a(11) =2057a(12) =3888a(13) =7339a(14) =13862a(15) =26179a(16) =49437a(17) =93366a(18) =176321a(19) =332986a(20) =628852a(21) =1187596a(22) =2242800a(23) =4235569a(24) =7998951a(25) =15106172a(26) =28528288a(27) =53876211a(28) =101746240a(29) =192149690