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 A245356 #8 Oct 02 2021 06:02:46 %S A245356 4,4,4,4,8,8,12,16,20,28,36,48,64,88,116,156,208,276,368,492,656,872, %T A245356 1164,1552,2068,2760,3680,4904,6540,8720,11628,15504,20672,27560, %U A245356 36748,48996,65328,87104,116140,154852,206472,275296,367060,489412,652552,870068 %N A245356 Number of numbers whose base-4/3 expansion (see A024631) has n digits. %F A245356 a(n) = 4*A072493(n). %e A245356 a(3) = 4 because 320, 321, 322, and 323 are the base-4/3 expansions for the numbers 9, 10, 11, and 12 respectively and these are the only numbers with 3 digits. %o A245356 (Sage) %o A245356 A=[1] %o A245356 for i in [1..60]: %o A245356 A.append(ceil(((4-3)/3)*sum(A))) %o A245356 [4*x for x in A] %Y A245356 Cf. A072493, A024631, A081848. %K A245356 nonn,base %O A245356 1,1 %A A245356 _Hailey R. Olafson_, Jul 18 2014