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 A090842 #13 Jan 14 2025 01:53:05
%S A090842 1,1,4,1,5,10,1,6,17,22,1,7,26,53,46,1,8,37,106,161,94,1,9,50,187,426,
%T A090842 485,190,1,10,65,302,937,1706,1457,382,1,11,82,457,1814,4687,6826,
%U A090842 4373,766,1,12,101,658,3201,10886,23437,27306,13121,1534,1,13,122,911,5266
%N A090842 Square array of numbers read by antidiagonals where T(n,k) = ((k+3)*(k+2)^n-2)/(k+1).
%C A090842 Nodes on a tree with degree k interior nodes and degree 1 boundary nodes.
%H A090842 L. He, X. Liu and G. Strang, <a href="http://www-math.mit.edu/~gs/papers/mp.pdf">Trees with Cantor Eigenvalue Distribution</a>, Studies in Applied Mathematics 110 (2), 123-138, 2003.
%F A090842 The total number of nodes on a tree with degree k interior nodes and degree 1 boundary nodes is given by N(k, r) = (k*(k-1)^r-2)/(k-2).
%F A090842 G.f.: Sum_{k>=0} (1+x*y)/(1-x*y)/(1-(k+2)*x*y)*y^k. - _Vladeta Jovovic_, Dec 12 2003
%e A090842 Rows begin:
%e A090842 1 4 10 22 ...
%e A090842 1 5 17 53 ...
%e A090842 1 6 26 106 ...
%e A090842 1 7 37 187 ...
%Y A090842 Rows include A033484, A048473, A020989, A057651, A061801, A090843.
%K A090842 easy,nonn,tabl
%O A090842 0,3
%A A090842 _Paul Barry_, Dec 09 2003