a(n) is the smallest k such that A261786(k) >= 3^n.

Terms

a(0) =1a(1) =2a(2) =5a(3) =12a(4) =30a(5) =81a(6) =224a(7) =626a(8) =1747a(9) =4909a(10) =13811a(11) =38934a(12) =109889a(13) =310666a(14) =880125a(15) =2500221a(16) =7125406a(17) =20376598a(18) =58472481a(19) =168349612a(20) =486198698a(21) =1408140693a(22) =4088769215a(23) =11899761717a(24) =34703682407