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 A093849 #13 Sep 08 2022 08:45:13
%S A093849 9,153,2097,26496,319995,3749994,42999985,484999992,5399999991,
%T A093849 59499999990,649999999935,7049999999988,75999999999924,
%U A093849 814999999999941,8699999999999985,92499999999999984,979999999999999902
%N A093849 Row sums of triangle A093846.
%H A093849 G. C. Greubel, <a href="/A093849/b093849.txt">Table of n, a(n) for n = 1..990</a>
%F A093849 a(n) = n*(2*10^(n-1) - 2 + (n+1)*floor(9*10^(n-1)/n))/2.
%t A093849 Table[n*(2*10^(n-1) -2 +(n+1)*Floor[9*10^(n-1)/n])/2, {n, 1, 20}] (* _G. C. Greubel_, Mar 22 2019 *)
%o A093849 (PARI) {a(n) = n*(2*10^(n-1) -2 +(n+1)*floor(9*10^(n-1)/n))/2}; \\ _G. C. Greubel_, Mar 22 2019
%o A093849 (Magma) [n*(2*10^(n-1) -2 +(n+1)*Floor(9*10^(n-1)/n))/2: n in [1..20]]; // _G. C. Greubel_, Mar 22 2019
%o A093849 (Sage) [n*(2*10^(n-1) -2 +(n+1)*floor(9*10^(n-1)/n))/2 for n in (1..20)] # _G. C. Greubel_, Mar 22 2019
%Y A093849 Cf. A093846.
%K A093849 base,easy,nonn
%O A093849 1,1
%A A093849 _Amarnath Murthy_, Apr 18 2004
%E A093849 Edited and extended by _David Wasserman_, Mar 26 2007