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 A026387 #13 Aug 27 2025 10:36:29 %S A026387 2,8,34,150,678,3116,14494,68032,321590,1528776,7301142,35003238, %T A026387 168359754,812041860,3926147730,19022666310,92338836390,448968093320, %U A026387 2186194166950,10659569748370,52037098259090,254308709196660 %N A026387 a(n) = number of integer strings s(0),...,s(n) counted by array T in A026386 that have s(n)=0; also a(n) = T(2n,n). %H A026387 László Németh, <a href="https://arxiv.org/abs/1905.13475">Tetrahedron trinomial coefficient transform</a>, arXiv:1905.13475 [math.CO], 2019. %F A026387 a(n) = A085362(n+1), n >= 0. - _Hartmut F. W. Hoft_, Jul 07 2024 %Y A026387 Essentially the same as A085362. %Y A026387 Cf. A026378. %K A026387 nonn,changed %O A026387 0,1 %A A026387 _Clark Kimberling_