Number of palindromes (in base 6) below 6^n.

Terms

a(0) =5a(1) =10a(2) =40a(3) =70a(4) =250a(5) =430a(6) =1510a(7) =2590a(8) =9070a(9) =15550a(10) =54430a(11) =93310a(12) =326590a(13) =559870a(14) =1959550a(15) =3359230a(16) =11757310a(17) =20155390a(18) =70543870a(19) =120932350a(20) =423263230a(21) =725594110a(22) =2539579390a(23) =4353564670a(24) =15237476350a(25) =26121388030a(26) =91424858110a(27) =156728328190a(28) =548549148670