Powers of sqrt(15) rounded to nearest integer.

Terms

a(0) =1a(1) =4a(2) =15a(3) =58a(4) =225a(5) =871a(6) =3375a(7) =13071a(8) =50625a(9) =196070a(10) =759375a(11) =2941047a(12) =11390625a(13) =44115701a(14) =170859375a(15) =661735514a(16) =2562890625a(17) =9926032709a(18) =38443359375a(19) =148890490632a(20) =576650390625