G.f. satisfies: A(x) = (1 + x*A(x)) * (1 + x^4*A(x)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =4a(6) =7a(7) =11a(8) =17a(9) =28a(10) =49a(11) =87a(12) =152a(13) =262a(14) =453a(15) =794a(16) =1408a(17) =2507a(18) =4462a(19) =7943a(20) =14179a(21) =25415a(22) =45713a(23) =82398a(24) =148731a(25) =268859a(26) =486890a(27) =883411a(28) =1605582a(29) =2922259