Number of vertex cuts in the n-helm graph.

Terms

a(0) =1a(1) =12a(2) =71a(3) =354a(4) =1617a(5) =7020a(6) =29563a(7) =122214a(8) =499493a(9) =2026848a(10) =8186895a(11) =32969754a(12) =132508729a(13) =531842196a(14) =2132610467a(15) =8545773774a(16) =34228238925a(17) =137046552264a(18) =548583066679