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 A384867 #11 Jun 11 2025 09:57:08 %S A384867 2,4,2,14,8,2,52,52,12,2,214,376,114,16,2,916,2998,1228,200,20,2,4116, %T A384867 25256,14568,2864,310,24,2,18996,222128,18,3132,45140,5540,444,28,2 %N A384867 Array A(T,k) read down antidiagonals: Number of typed decorated trees of cardinality T on k vertices with D=2 decorations. %C A384867 Is the array obtained by deleting each second column of A242249, transposing, and multiplying each entry by 2? %H A384867 L. Foissy, <a href="https://doi.org/10.3852/SIGMA.2021.086">Algebraic structures on typed decorated rooted trees</a>, SIGMA 17 (2021) 086, Appendix 6.1 D=2. %e A384867 Array starts with rows T=1,2,3.. and columns k=1,2,3.. as %e A384867 2 4 14 52 214 916 4116 18996 %e A384867 2 8 52 376 2998 25256 222128 2013680 %e A384867 2 12 114 1228 14568 183132 2401410 32465640 %e A384867 2 16 200 2864 45140 754640 13156232 236477200 %e A384867 2 20 310 5540 108930 2272804 49446000 1109081180 %e A384867 2 24 444 9512 224154 5606520 146204792 3930863232 %e A384867 2 28 602 15036 413028 12043500 366122190 11475005616 %e A384867 2 32 784 22368 701768 23373216 811575408 29052861280 %e A384867 2 36 990 31764 1120590 41969844 1638712716 65965167108 %e A384867 2 40 1220 43480 1703710 70875208 3073688160 %Y A384867 Cf. A242249 (D=1), A038055 (row 1), A136794 (row 2). %K A384867 nonn,tabl,more %O A384867 1,1 %A A384867 _R. J. Mathar_, Jun 11 2025