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 A097569 #12 Dec 08 2018 04:10:40
%S A097569 1,2,3,4,5,6,7,8,9,12,18,21,24,27,36,42,45,48,54,63,72,81,84,126,216,
%T A097569 243,247,364,423,481,486,846,2478,8463,24786
%N A097569 Right-truncatable Harshad numbers (zeros not permitted).
%C A097569 Harshad numbers in which repeatedly deleting the rightmost digit gives a Harshad number at every step until a single-digit Harshad number remains. Sequence is finite with 24786 being the last term.
%C A097569 24786 can be proved to be the last term by a genetic approach (constructing the whole tree). - _Carlos Rivera_, Sep 19 2004
%t A097569 harQ[n_]:=Module[{idn=IntegerDigits[n]},!MemberQ[idn,0]&&Divisible[n, Total[ idn]]]; rtQ[n_]:=Module[{idn=IntegerDigits[n],c}, c=Table[ FromDigits[ Take[ idn,i]],{i,Length[idn]}];And@@(harQ/@c)]; Select[ Range[25000],rtQ] (* _Harvey P. Dale_, Oct 07 2013 *)
%Y A097569 Cf. A005349.
%K A097569 base,nonn,fini,full
%O A097569 1,2
%A A097569 _Jason Earls_, Aug 28 2004