Integer part of zeta(zeta(n)).

Terms

a(0) =2a(1) =5a(2) =12a(3) =27a(4) =58a(5) =120a(6) =245a(7) =498a(8) =1006a(9) =2024a(10) =4064a(11) =8149a(12) =16327a(13) =32692a(14) =65435a(15) =130938a(16) =261966a(17) =524051a(18) =1048260a(19) =2096731a(20) =4193743a(21) =8387860a(22) =16776219a(23) =33553102a(24) =67107091a(25) =134215365a(26) =268432305a(27) =536866711a(28) =1073736223a(29) =2147476181