"DIK" (bracelet, indistinct, unlabeled) transform of 3,3,3,3...

Terms

a(0) =3a(1) =9a(2) =22a(3) =57a(4) =150a(5) =444a(6) =1362a(7) =4497a(8) =15338a(9) =54018a(10) =193722a(11) =705392a(12) =2593398a(13) =9612144a(14) =35840622a(15) =134318097a(16) =505486878a(17) =1909275084a(18) =7234415562a(19) =27489389850a(20) =104718539638a(21) =399828796884