Floor(sqrt(7*2^n)).

Terms

a(0) =2a(1) =3a(2) =5a(3) =7a(4) =10a(5) =14a(6) =21a(7) =29a(8) =42a(9) =59a(10) =84a(11) =119a(12) =169a(13) =239a(14) =338a(15) =478a(16) =677a(17) =957a(18) =1354a(19) =1915a(20) =2709a(21) =3831a(22) =5418a(23) =7662a(24) =10836a(25) =15325a(26) =21673a(27) =30651a(28) =43347a(29) =61303