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 A073637 #9 May 01 2013 21:13:43
%S A073637 8,9,8,1,8,1,8,1,8,8,1,1,8,1,8,8,8,1,1,8,1,1,8,8,1,8,1,8,1,8,1,8,8,1,
%T A073637 8,1,1,1,8,8,8,1,8,1,8,1,1,1,8,1,8,8,1,8,8,8,8,1,1,8,1,8,1,8,1,8,1,1,
%U A073637 8,1,8,8,1,1,1,8,8,1,8,1,8,1,8,1,1,8,8,1,8,1,8,8,1,8,1,8,8,8,1,1
%N A073637 Digital root (cf. A010888) of prime(n)^3.
%C A073637 Apart from a(2)=9 all other terms are either 1 or 8.
%e A073637 a(3)=8 because p(3)=5 and 5^3=125 -> sum-of-digits = 8. a(4)=1 because p(3)=7 and 7^3=343 -> sum-of-digits = 10 -> sum-of-digits = 1.
%t A073637 n=3; su[x_] := Sum[IntegerDigits[x][[i]], {i, Length[IntegerDigits[x]]}]; Table[su[su[su[su[Prime[x]^n]]]], {x, 100}]
%t A073637 Table[If[(m9=Mod[Prime[n]^3,9])==0,9,m9],{n,200}]
%Y A073637 Cf. A010888, A021596, A056992, A010888, A038194, A166923.
%K A073637 nonn,base
%O A073637 1,1
%A A073637 _Zak Seidov_, Sep 01 2002, Oct 23 2009
%E A073637 Edited by _N. J. A. Sloane_, Oct 29 2009