Arkons: number of elementary maps with n-1 nodes.

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =4a(5) =10a(6) =34a(7) =112a(8) =398a(9) =1443a(10) =5387a(11) =20482a(12) =79177a(13) =310102a(14) =1228187a(15) =4910413a(16) =19792582a(17) =80343445a(18) =328159601a(19) =1347699906a(20) =5561774999a(21) =23052871229a(22) =95926831442a(23) =400587408251