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 A242622 #7 Jul 17 2014 21:23:10 %S A242622 1,1,2,6,21,77,287,1079,4082,15522,59271,227131,873051,3364827, %T A242622 12998867,50321075,195162350,758156366,2949614789,11490869489, %U A242622 44819531180,175009397380,684059403670,2676260628574,10479320689274,41065736472890,161043272100440,631974335773536 %N A242622 a(n) = number of numbers with digit sum n, not greater than the n-th repunit (cf. A052222). %C A242622 a(n) = length of row n in triangle A242614. %H A242622 Jens Kruse Andersen, <a href="/A242622/b242622.txt">Table of n, a(n) for n = 0..100</a> %o A242622 (Haskell) %o A242622 a242622 = length . a242614_row %o A242622 (PARI) \\ c[x,y] = #numbers < 10^x with digit sum y-1. %o A242622 m=50; c=matrix(m,m+1); for(x=1, m, for(y=1, m+1, c[x,y]=sum(d=0, min(9,y-1), if(x>1, c[x-1,y-d], d==y-1)))); for(n=0, m, print1(1+sum(i=2, n, c[i-1,i+1])", ")); \\ _Jens Kruse Andersen_, Jul 17 2014 %K A242622 nonn,base %O A242622 0,3 %A A242622 _Reinhard Zumkeller_, Jul 16 2014 %E A242622 More terms from _Jens Kruse Andersen_, Jul 17 2014