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 A068883 #10 Mar 24 2024 15:32:13 %S A068883 1,10,105,1830,10585,107416,1038961,10109256,101410161,1014503490, %T A068883 10143650961,101072103210,1012143638925,10101274165450, %U A068883 101014143472945,1010363290981278,10101078125834905,101012169252147076,1010125816103490141 %N A068883 Smallest n-digit triangular numbers with property that digits alternate in parity, or 0 if no such number exists. %H A068883 Sean A. Irvine, <a href="/A068883/b068883.txt">Table of n, a(n) for n = 1..50</a> %e A068883 a(4) = 1830 is a term as 1, 8, 3 and 0 have odd and even parity alternately. %Y A068883 Cf. A068876, A030152, A068882, A068884. %K A068883 base,nonn %O A068883 1,2 %A A068883 _Amarnath Murthy_, Mar 19 2002 %E A068883 a(7)-a(18) from _Donovan Johnson_, Mar 14 2010 %E A068883 a(19) from _Donovan Johnson_, Mar 11 2011