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A342913 Pairwise listing of the partitions of 2k into two parts, (s,t), with 0 < t <= s ordered by decreasing values of s and where k = 1,2,... . 1

%I #6 Mar 28 2021 19:34:24

%S 1,1,3,1,2,2,5,1,4,2,3,3,7,1,6,2,5,3,4,4,9,1,8,2,7,3,6,4,5,5,11,1,10,

%T 2,9,3,8,4,7,5,6,6,13,1,12,2,11,3,10,4,9,5,8,6,7,7,15,1,14,2,13,3,12,

%U 4,11,5,10,6,9,7,8,8,17,1,16,2,15,3,14,4,13,5,12,6,11,7

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

%H <a href="/index/Par#part">Index entries for sequences related to partitions</a>

%F a(n) = k - (k^2 + k - m)*(-1)^n / 2, where k = round(sqrt(m)) and m = 2*floor((n+1-(-1)^n)/2).

%F a(n) = A342769(A103889(n)).

%e [13,1]

%e [11,1] [12,2]

%e [9,1] [10,2] [11,3]

%e [7,1] [8,2] [9, 3] [10,4]

%e [5,1] [6,2] [7,3] [8, 4] [9, 5]

%e [3,1] [4,2] [5,3] [6,4] [7, 5] [8, 6]

%e [1,1] [2,2] [3,3] [4,4] [5,5] [6, 6] [7, 7]

%e 2k 2 4 6 8 10 12 14

%e --------------------------------------------------------------------------

%e 2k Decreasing partitions of 2k

%e --------------------------------------------------------------------------

%e 2 1,1

%e 4 3,1,2,2

%e 6 5,1,4,2,3,3

%e 8 7,1,6,2,5,3,4,4

%e 10 9,1,8,2,7,3,6,4,5,5

%e 12 11,1,10,2,9,3,8,4,7,5,6,6

%e 14 13,1,12,2,11,3,10,4,9,5,8,6,7,7

%e ...

%Y Cf. A000194, A052928, A103889, A339399, A339443, A342769.

%K nonn

%O 1,3

%A _Wesley Ivan Hurt_, Mar 28 2021

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Last modified September 2 18:29 EDT 2024. Contains 375616 sequences. (Running on oeis4.)