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 A282766 #14 Mar 13 2017 13:03:39 %S A282766 50,642,1284,1926,2292,5088,29828,42922,53046,95968,512050,1043160, %T A282766 1723714,14819056,154860206,159251186,752516578,946218018,54728972948 %N A282766 n/2 analog of Keith numbers. %C A282766 Like Keith numbers but starting from n/2 digits to reach n. %C A282766 Consider the digits of n/2. Take their sum and repeat the process deleting the first addend and adding the previous sum. The sequence lists the numbers that after some iterations reach a sum equal to themselves. %C A282766 If it exists, a(20) > 10^12. - _Lars Blomberg_ Mar 13 2017 %e A282766 642/2 = 321: %e A282766 3 + 2 + 1 = 6; %e A282766 2 + 1 + 6 = 9; %e A282766 1 + 6 + 9 = 16; %e A282766 6 + 9 + 16 = 31; %e A282766 9 + 16 + 31 = 56; %e A282766 16 + 31 + 56 = 103; %e A282766 31 + 56 + 103 = 190; %e A282766 56 + 103 + 190 = 349; %e A282766 103 + 190 + 349 = 642. %p A282766 with(numtheory): P:=proc(q,h,w) local a, b, k, n, t, v; v:=array(1..h); %p A282766 for n from 1/w by 1/w to q do a:=w*n; b:=ilog10(a)+1; if b>1 then %p A282766 for k from 1 to b do v[b-k+1]:=(a mod 10); a:=trunc(a/10); od; t:=b+1; v[t]:=add(v[k], k=1..b); %p A282766 while v[t]<n do t:=t+1; v[t]:=add(v[k], k=t-b..t-1); od; %p A282766 if v[t]=n then print(n); fi; fi; od; end: P(10^6, 1000,1/2); %t A282766 With[{n = 2}, Select[Range[10 n, 10^6, n], Function[k, Last@ NestWhile[Append[Rest@ #, Total@ #] &, IntegerDigits[k/n], Total@ # <= k &] == k]]] (* _Michael De Vlieger_, Feb 27 2017 *) %Y A282766 Cf. A282757-A282765, A282767, A282768, A282769. %K A282766 nonn,base,more %O A282766 1,1 %A A282766 _Paolo P. Lava_, Feb 27 2017 %E A282766 a(15)-a(19) from _Lars Blomberg_, Mar 13 2017