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 A068134 #19 May 26 2025 00:24:51 %S A068134 0,1,2,3,7,12,56,109,368,1332,5656,28248,140547,774325,8485151, %T A068134 34339452,397492132,3996973827,63229707890,1039037824132, %U A068134 10853561442116,305279835527631,4240235842471234,117388244641426491,3997445934568646292,99999889989926488708 %N A068134 Index of the smallest triangular number with digit sum = n-th triangular number. %Y A068134 Cf. A068133. %K A068134 base,nonn %O A068134 0,3 %A A068134 _Amarnath Murthy_, Feb 21 2002 %E A068134 More terms from Larry Reeves (larryr(AT)acm.org), Jun 17 2002 %E A068134 a(18)-a(19) from _Max Alekseyev_, Jun 19 2011 %E A068134 a(0)=0 inserted by _Sean A. Irvine_, Jan 29 2024 %E A068134 a(20)-a(25) from _Max Alekseyev_, May 25 2025