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 A329725 #43 Nov 29 2019 12:01:08
%S A329725 0,0,0,0,0,0,0,0,0,9,1,9,1,9,1,9,1,9,1,17,2,16,1,15,0,14,-1,13,-2,29,
%T A329725 -1,27,-3,25,-5,23,-7,21,-9,45,-8,42,-11,39,-14,36,-17,33,-20,65,-19,
%U A329725 61,-23,57,-27,53,-31,49,-35,89,-34,84,-39,79,-44,74,-49,69,-54,117
%N A329725 a(1)=0, a(n) = n - (product of nonzero digits of n) - a(n-1).
%C A329725 a(10n+1)-a(10n-1)=1 for all positive integer n (conjectured).
%H A329725 Joshua Oliver, <a href="/A329725/b329725.txt">Table of n, a(n) for n = 1..5000</a>
%F A329725 a(n) = Sum_{k=2..n} (-1)^(n-k)*A063543(k). - _Robert Israel_, Nov 20 2019
%e A329725 a(22) = 22 - 2*2 - 2 = 16.
%p A329725 R:= ListTools:-PartialSums(map(n -> (-1)^n*(n - convert(subs(0=NULL,convert(n,base,10)),`*`)), [$1..100])):
%p A329725 seq((-1)^n*R[n],n=1..100); # _Robert Israel_, Nov 20 2019
%t A329725 Nest[Append[#1, #2 - Last[#1] - Times @@ DeleteCases[IntegerDigits[#2], 0]] & @@ {#, Length@ # + 1} &, {0}, 69] (* _Michael De Vlieger_, Nov 19 2019 *)
%o A329725 (PARI) for (n=1, 70, print1 (v=if (n==1, 0, n - vecprod(select(sign, digits(n))) - v)", ")) \\ _Rémy Sigrist_, Nov 28 2019
%Y A329725 Cf. A063108, A063543.
%K A329725 sign,base,look
%O A329725 1,10
%A A329725 _Joshua Oliver_, Nov 19 2019