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 A173108 #11 Nov 19 2022 15:55:38 %S A173108 1,1,2,1,5,1,15,2,1,52,5,1,203,15,2,1,877,52,5,1,4140,203,15,2,1, %T A173108 21147,877,52,5,1,115975,4140,203,15,2,1,678570,21147,877,52,5,1, %U A173108 4213597,115975,4140,203,15,2,1,27644437,678570,21147,877,52,5,1 %N A173108 Triangle, A000110 in every column > 0, shifted down twice. %C A173108 Row sums = A173109: (1, 1, 3, 6, 18, 58, 221, 935, ...). %C A173108 Let the triangle = M. Then lim_{n->oo} M^n = A173110: (1, 1, 3, 6, 20, 60, ...). %F A173108 Bell sequence in every column, for columns > 0, shifted down twice. %e A173108 First few rows of the triangle: %e A173108 1; %e A173108 1; %e A173108 2, 1; %e A173108 5, 1; %e A173108 15, 2, 1; %e A173108 52, 5, 1; %e A173108 203, 15, 2, 1; %e A173108 877, 52, 5, 1; %e A173108 4140, 203, 15, 2, 1; %e A173108 21147, 877, 52, 5, 1; %e A173108 115975, 4140, 203, 15, 2, 1; %e A173108 ... %t A173108 T[n_, k_] := BellB[n - 2 k]; %t A173108 Table[T[n, k], {n, 0, 10}, {k, 0, Quotient[n, 2]}] // Flatten (* _Jean-François Alcover_, Apr 22 2022 *) %o A173108 (PARI) B(n) = sum(k=0, n, stirling(n, k, 2)); \\ A000110 %o A173108 tabf(nn) = for (n=0, nn, for(k=0, n\2, print1(B(n-2*k), ", "));); \\ _Michel Marcus_, Nov 19 2022 %Y A173108 Cf. A000110, A173109, A173110, A173111. %K A173108 nonn,tabf %O A173108 0,3 %A A173108 _Gary W. Adamson_, Feb 09 2010 %E A173108 Keyword tabf and more terms from _Michel Marcus_, Nov 19 2022