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 A162845 #6 Mar 04 2019 00:20:23 %S A162845 1,3,6,12,18,6,24,18,27,39,18,36,36,36,42,60,63,63,78,72,72,63,72,90, %T A162845 72,99,90,75,117,108,90,99,117,117,99,162,126,144,153,153,153,159,150, %U A162845 126,153,114,144,171,171,171,162,162,198,180,186,207,180,189,180,234,207 %N A162845 Sum of digits of binomial(3n,n). %e A162845 a(4)=sum of digits of binomial(3*4,4)=18 because binomial(3*4,4)=495. %p A162845 a := proc (n) local nn: nn := convert(binomial(3*n, n), base, 10): add(nn[j], j = 1 .. nops(nn)) end proc: seq(a(n), n = 0 .. 70); # _Emeric Deutsch_, Jul 29 2009 %K A162845 nonn,base %O A162845 0,2 %A A162845 _Yalcin Aktar_, Jul 14 2009 %E A162845 Extended by _Emeric Deutsch_, Jul 29 2009