a(n) is the total number of pentagrams in a pentagram fractal after n iterations.

Terms

a(0) =1a(1) =6a(2) =26a(3) =76a(4) =191a(5) =411a(6) =816a(7) =1521a(8) =2726a(9) =4741a(10) =8081a(11) =13566a(12) =22536a(13) =37146a(14) =60896a(15) =99436a(16) =161921a(17) =263151a(18) =427086a(19) =692481a(20) =1122056a(21) =1817281a(22) =2942351a(23) =4762926a(24) =7708866a(25) =12475686a(26) =20188766a(27) =32668996a(28) =52862651a(29) =85536891