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 A111329 #12 Feb 16 2025 08:32:58
%S A111329 2,15,7,101,22,490,56,1958,135,6842,297,21637,627,63261,1255,173525,
%T A111329 2436,451276,4565,1121505,8349,2679689,14883,6185689,26015,13848650,
%U A111329 44583,30167357,75175,64112359,124754,133230930,204226,271248950,329931
%N A111329 Number of partitions of T where T = (3n + 1) if n is even and T=(3n + 1)/2 if n is odd.
%H A111329 Jeffrey C. Lagarias <a href="http://arXiv.org/abs/math/0309224">The 3x+1 problem: An annotated bibliography</a> arXiv:math/0309224 [math.NT], 2003-2011.
%H A111329 Jeffrey C. Lagarias, <a href="http://www.cecm.sfu.ca/organics/papers/lagarias/">"The Problem and Its Generalizations." Amer. Math. Monthly 92, 3-23, 1985.</a>
%H A111329 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CollatzProblem.html">Collatz Problem</a>
%F A111329 a(n) = A000041(A165355(n-1)). [_Reinhard Zumkeller_, Nov 19 2009]
%e A111329 If n=1 then T = 2 and a(1) = 2.
%t A111329 f[n_] := If[EvenQ[n], PartitionsP[3n + 1], PartitionsP[(3n + 1)/2]]; Table[ f[n], {n, 35}] (* _Robert G. Wilson v_, Nov 07 2005 *)
%Y A111329 Cf. A000546, A070165, A006577.
%K A111329 nonn
%O A111329 1,1
%A A111329 _Parthasarathy Nambi_, Nov 04 2005