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 A257295 #20 May 11 2015 18:45:28 %S A257295 0,1,2,3,4,5,6,7,8,9,1,1,2,2,3,3,4,4,5,5,1,2,2,3,3,4,4,5,5,6,2,2,3,3, %T A257295 4,4,5,5,6,6,2,3,3,4,4,5,5,6,6,7,3,3,4,4,5,5,6,6,7,7,3,4,4,5,5,6,6,7, %U A257295 7,8,4,4,5,5,6,6,7,7,8,8,4,5,5,6,6,7,7,8,8,9,5,5,6,6,7,7,8,8,9,9,0,1,1,1,2,2,2,3 %N A257295 Arithmetic mean of the digits of n, rounded to the nearest integer. %C A257295 Coincides up to a(99) with the variant A004427 (= arithmetic mean of digits, rounded up). - _M. F. Hasler_, May 10 2015 %C A257295 0 <= a(n) <= 9. a(10*n + a(n)) = a(n). - _Robert Israel_, May 11 2015 %H A257295 <a href="/index/Coi#Colombian">Index entries for Colombian or self numbers and related sequences</a> %F A257295 a(n) = round(A007953(n)/A055642(n)). %F A257295 A004426(n) <= a(n) <= A004427(n). %p A257295 f:= proc(n) local L; %p A257295 L:= convert(n,base,10); %p A257295 round(convert(L,`+`)/nops(L)) %p A257295 end proc: %p A257295 map(f, [$0..100]); # _Robert Israel_, May 11 2015 %t A257295 Round[Mean[IntegerDigits[#]]]&/@Range[0,110] %o A257295 (PARI) A257295(n)=round(sum(i=1, #n=digits(n), n[i])/#n) \\ ...Vecsmall(Str(n))...-48 is a little faster. %o A257295 (PARI) a(n)=round(sumdigits(n)/#digits(n)) \\ _Charles R Greathouse IV_, May 11 2015 %Y A257295 Cf. A004426, A004427, A007953, A055642, A004428, A004429. %K A257295 nonn,base,easy %O A257295 0,3 %A A257295 _M. F. Hasler_, May 10 2015