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 A031299 #21 May 21 2025 06:33:15 %S A031299 0,10,30,50,70,90,110,130,150,170,190,191,194,197,200,203,206,209,212, %T A031299 215,218,220,250,280,310,340,370,400,430,460,490,491,494,497,500,503, %U A031299 506,509,512,515,518,520,550,580,610,640,670,700 %N A031299 Position of n-th 0 in A031298. %o A031299 (PARI) T(n, k) = n\10^(k-1)%10; \\ A031298 %o A031299 lista(nn) = my(j=0, list = List()); for (n=0, nn, for (k=1, #Str(n), if (T(n,k) == 0, listput(list, j)); j++;);); Vec(list); \\ _Michel Marcus_, Jan 26 2023 %Y A031299 Cf. A031298. %K A031299 nonn,base %O A031299 1,2 %A A031299 _Clark Kimberling_ %E A031299 0 added by _Arkadiusz Wesolowski_, Jan 10 2012