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 A292901 #16 Aug 11 2025 05:23:24 %S A292901 1,1,2,1,2,6,1,2,3,1,1,2,12,3,30,1,2,24,9,20,1,1,2,48,54,80,10,42,1,2, %T A292901 96,324,8640,200,105,1,1,2,192,1944,3840,36000,525,35,30,1,2,384, %U A292901 11664,1244160,720000,756000,3675,168,1 %N A292901 Triangle read by rows, a generalization of the Bernoulli numbers, the denominators for n>=0 and 0<=k<=n. %C A292901 See comments in A292900. %H A292901 S. Fukuhara, N. Kawazumi and Y. Kuno, <a href="https://arxiv.org/abs/1505.04840">Generalized Kronecker formula for Bernoulli numbers and self-intersections of curves on a surface</a>, arXiv:1505.04840 [math.NT], 2015. %H A292901 L. Kronecker, <a href="https://gdz.sub.uni-goettingen.de/id/PPN243919689_0094">Ueber die Bernoullischen Zahlen</a>, J. Reine Angew. Math. 94 (1883), 268-269. %e A292901 Triangle starts: %e A292901 [0], 1 %e A292901 [1], 1, 2 %e A292901 [2], 1, 2, 6 %e A292901 [3], 1, 2, 3, 1 %e A292901 [4], 1, 2, 12, 3, 30 %e A292901 [5], 1, 2, 24, 9, 20, 1 %e A292901 [6], 1, 2, 48, 54, 80, 10, 42 %e A292901 [7], 1, 2, 96, 324, 8640, 200, 105, 1 %e A292901 [8], 1, 2, 192, 1944, 3840, 36000, 525, 35, 30 %e A292901 [9], 1, 2, 384, 11664, 1244160, 720000, 756000, 3675, 168, 1 %p A292901 # Function B(n,k) in A292900. %p A292901 for n from 0 to 9 do seq(denom(B(n, k)), k=0..n) od; %t A292901 B[0, 0] = 1; B[n_, k_] := Sum[(-1)^(j-n)/(j+1) Binomial[k+1, j+1] Sum[i^n (j-i+1)^(k-n), {i, 0, j}], {j, 0, k}]; Table[B[n, k] // Denominator, {n, 0, 9}, {k, 0, n}] // Flatten (* _Jean-François Alcover_, Feb 14 2019, from Maple *) %Y A292901 Cf. A292900 (numerators), T(n, n) = A027642(n). %K A292901 nonn,tabl,frac %O A292901 0,3 %A A292901 _Peter Luschny_, Oct 01 2017