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 A068889 #7 Mar 22 2024 18:36:48 %S A068889 1,6,10,36,78,105,210,325,496,561,630,703,2145,2701,6105,6903,8385, %T A068889 23436,30381,41616,50721,67896,70125,81810,90525,210925,214185,230181, %U A068889 232903,254541,258121,290703,414505,454581,490545,498501,634501,674541,810901,852165 %N A068889 Triangular numbers with property that digits alternate in parity individually as well as in concatenation with previous terms. %Y A068889 Cf. A068882. %K A068889 base,nonn %O A068889 1,2 %A A068889 _Amarnath Murthy_, Mar 20 2002 %E A068889 Corrected and extended by _Sean A. Irvine_, Mar 22 2024