This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A245416 #10 Jul 22 2014 20:12:23 %S A245416 9,36,162,729,3276,14742,66339,298530,1343385,6045228,27203526, %T A245416 122415867,550871406,2478921327,11155145967,50198156856,225891705852, %U A245416 1016512676334,4574307043503,20584381695759,92629717630920,416833729339140,1875751782026130 %N A245416 Number of nonnegative integers with property that their base 9/2 expansion (see A024650) has n digits. %e A245416 The numbers 9-44 are represented by 20, 21, 22, 23, 24, 25, 26, 27, 28, 40, 41, 42, 43, 44, 45, 46, 47, 48, 60, 61, 62, 63, 64, 65, 66, 67, 68, 80, 81, 82, 83, 84, 85, 86, 87, 88 respectively in base 9/2. These are the only integers with two digits, and so a(2)=36. %o A245416 (Sage) %o A245416 A=[1] %o A245416 for i in [1..60]: %o A245416 A.append(ceil((9-2)/2*sum(A))) %o A245416 [9*x for x in A] %Y A245416 Cf. A024650, A081848. %K A245416 nonn,base %O A245416 1,1 %A A245416 _James Van Alstine_, Jul 21 2014