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

Terms

a(0) =1a(1) =6a(2) =21a(3) =51a(4) =106a(5) =201a(6) =361a(7) =626a(8) =1061a(9) =1771a(10) =2926a(11) =4801a(12) =7841a(13) =12766a(14) =20741a(15) =33651a(16) =54546a(17) =88361a(18) =143081a(19) =231626a(20) =374901a(21) =606731a(22) =981846a(23) =1588801a(24) =2570881a(25) =4159926a(26) =6731061a(27) =10891251a(28) =17622586a(29) =28514121