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 A332690 #21 Feb 21 2020 17:02:08 %S A332690 0,1,12,124,1248,12496,124992,1249984,12499968,124999936,1249999862, %T A332690 12499999623,124999998144,1249999984364,12499999840480, %U A332690 124999998308464,1249999981991936,12499999808733888,124999997974967808,1249999978624935680,12499999774999871588 %N A332690 Sum of all numbers in bijective base-9 numeration with digit sum n. %C A332690 Different from A016134. %H A332690 Alois P. Heinz, <a href="/A332690/b332690.txt">Table of n, a(n) for n = 0..1000</a> %H A332690 Wikipedia, <a href="https://en.wikipedia.org/wiki/Bijective_numeration">Bijective numeration</a> %H A332690 <a href="/index/Rec#order_18">Index entries for linear recurrences with constant coefficients</a>, signature (10,1,-8,-17,-26,-35,-44,-53,-62,-81,-72,-63,-54,-45,-36,-27,-18,-9). %F A332690 G.f.: (Sum_{j=1..9} j*x^j) / ((B(x) - 1) * (9*B(x) - 1)) with B(x) = Sum_{j=1..9} x^j. %F A332690 a(n) = A028904(A332691(n)). %F A332690 a(n) = A016134(n-1) for n = 1..9. %e A332690 a(2) = 12 = 2 + 10 = 2_bij9 + 11_bij9. %p A332690 b:= proc(n) option remember; `if`(n=0, [1, 0], add((p-> %p A332690 [p[1], p[2]*9+p[1]*d])(b(n-d)), d=1..min(n, 9))) %p A332690 end: %p A332690 a:= n-> b(n)[2]: %p A332690 seq(a(n), n=0..23); %Y A332690 Cf. A007953, A016134, A028904, A052382, A211072, A214676, A332691. %K A332690 nonn,base,easy %O A332690 0,3 %A A332690 _Alois P. Heinz_, Feb 19 2020