cp's OEIS Frontend

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.

A342769 Pairwise listing of the partitions of 2k into two parts, (s,t), with 0 < s <= t ordered by increasing values of s and where k = 1,2,... .

This page as a plain text file.
%I A342769 #9 May 09 2021 12:56:29
%S A342769 1,1,1,3,2,2,1,5,2,4,3,3,1,7,2,6,3,5,4,4,1,9,2,8,3,7,4,6,5,5,1,11,2,
%T A342769 10,3,9,4,8,5,7,6,6,1,13,2,12,3,11,4,10,5,9,6,8,7,7,1,15,2,14,3,13,4,
%U A342769 12,5,11,6,10,7,9,8,8,1,17,2,16,3,15,4,14,5,13,6,12,7
%N A342769 Pairwise listing of the partitions of 2k into two parts, (s,t), with 0 < s <= t ordered by increasing values of s and where k = 1,2,... .
%H A342769 <a href="/index/Par#part">Index entries for sequences related to partitions</a>
%F A342769 a(n) = k + (k^2 + k - m)*(-1)^n / 2, where k = round(sqrt(m)) and m = 2*floor((n+1)/2).
%F A342769 a(n) = A342913(A103889(n)). - _Wesley Ivan Hurt_, May 09 2021
%e A342769                                                         [1,13]
%e A342769                                                [1,11]   [2,12]
%e A342769                                        [1,9]   [2,10]   [3,11]
%e A342769                                [1,7]   [2,8]   [3, 9]   [4,10]
%e A342769                        [1,5]   [2,6]   [3,7]   [4, 8]   [5, 9]
%e A342769                [1,3]   [2,4]   [3,5]   [4,6]   [5, 7]   [6, 8]
%e A342769        [1,1]   [2,2]   [3,3]   [4,4]   [5,5]   [6, 6]   [7, 7]
%e A342769    2k    2       4       6       8       10      12       14
%e A342769   --------------------------------------------------------------------------
%e A342769    2k   Nondecreasing partitions of 2k
%e A342769   --------------------------------------------------------------------------
%e A342769    2   1,1
%e A342769    4   1,3,2,2
%e A342769    6   1,5,2,4,3,3
%e A342769    8   1,7,2,6,3,5,4,4
%e A342769   10   1,9,2,8,3,7,4,6,5,5
%e A342769   12   1,11,2,10,3,9,4,8,5,7,6,6
%e A342769   14   1,13,2,12,3,11,4,10,5,9,6,8,7,7
%e A342769   ...
%Y A342769 Cf. A000194, A052928, A103889, A339399, A339443, A342913.
%K A342769 nonn,tabf
%O A342769 1,4
%A A342769 _Wesley Ivan Hurt_, Mar 21 2021