Number of lines in a Pauli graph of order n.

Terms

a(0) =15a(1) =45a(2) =153a(3) =561a(4) =2145a(5) =8385a(6) =33153a(7) =131841a(8) =525825a(9) =2100225a(10) =8394753a(11) =33566721a(12) =134242305a(13) =536920065a(14) =2147581953a(15) =8590131201a(16) =34360131585a(17) =137439739905a(18) =549757386753