Number of palindromes (in base 8) below 8^n.

Terms

a(0) =7a(1) =14a(2) =70a(3) =126a(4) =574a(5) =1022a(6) =4606a(7) =8190a(8) =36862a(9) =65534a(10) =294910a(11) =524286a(12) =2359294a(13) =4194302a(14) =18874366a(15) =33554430a(16) =150994942a(17) =268435454a(18) =1207959550a(19) =2147483646a(20) =9663676414a(21) =17179869182a(22) =77309411326a(23) =137438953470a(24) =618475290622