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A367399 Number of strict integer partitions of n whose length is not the sum of any two distinct parts.

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%I A367399 #6 Nov 20 2023 08:18:21
%S A367399 1,1,1,2,2,3,3,4,5,7,8,10,13,15,19,22,27,31,38,43,51,59,70,79,94,107,
%T A367399 124,143,165,188,218,248,283,324,369,419,476,540,610,691,778,878,987,
%U A367399 1111,1244,1399,1563,1750,1954,2184,2432,2714,3016,3358,3730,4143
%N A367399 Number of strict integer partitions of n whose length is not the sum of any two distinct parts.
%e A367399 The strict partition y = (6,4,2,1) has semi-sums {3,5,6,7,8,10}, which do not include 4, so y is counted under a(13).
%e A367399 The a(6) = 3 through a(13) = 15 strict partitions:
%e A367399   (6)    (7)    (8)      (9)      (10)     (11)     (12)       (13)
%e A367399   (4,2)  (4,3)  (5,3)    (5,4)    (6,4)    (6,5)    (7,5)      (7,6)
%e A367399   (5,1)  (5,2)  (6,2)    (6,3)    (7,3)    (7,4)    (8,4)      (8,5)
%e A367399          (6,1)  (7,1)    (7,2)    (8,2)    (8,3)    (9,3)      (9,4)
%e A367399                 (4,3,1)  (8,1)    (9,1)    (9,2)    (10,2)     (10,3)
%e A367399                          (4,3,2)  (5,3,2)  (10,1)   (11,1)     (11,2)
%e A367399                          (5,3,1)  (5,4,1)  (5,4,2)  (5,4,3)    (12,1)
%e A367399                                   (6,3,1)  (6,3,2)  (6,4,2)    (6,4,3)
%e A367399                                            (6,4,1)  (6,5,1)    (6,5,2)
%e A367399                                            (7,3,1)  (7,3,2)    (7,4,2)
%e A367399                                                     (7,4,1)    (7,5,1)
%e A367399                                                     (8,3,1)    (8,3,2)
%e A367399                                                     (5,4,2,1)  (8,4,1)
%e A367399                                                                (9,3,1)
%e A367399                                                                (6,4,2,1)
%t A367399 Table[Length[Select[IntegerPartitions[n], UnsameQ@@#&&FreeQ[Total/@Subsets[#,{2}], Length[#]]&]], {n,0,15}]
%Y A367399 The following sequences count and rank integer partitions and finite sets according to whether their length is a subset-sum, linear combination, or semi-sum of the parts. The current sequence is starred.
%Y A367399              sum-full  sum-free  comb-full comb-free semi-full semi-free
%Y A367399             -----------------------------------------------------------
%Y A367399 partitions:  A367212   A367213   A367218   A367219   A367394   A367398
%Y A367399 strict:      A367214   A367215   A367220   A367221   A367395   A367399*
%Y A367399 subsets:     A367216   A367217   A367222   A367223   A367396   A367400
%Y A367399 ranks:       A367224   A367225   A367226   A367227   A367397   A367401
%Y A367399 A000041 counts partitions, strict A000009.
%Y A367399 A002865 counts partitions whose length is a part, complement A229816.
%Y A367399 A365924 counts incomplete partitions, strict A365831.
%Y A367399 A236912 counts partitions with no semi-sum of the parts, ranks A364461.
%Y A367399 A237667 counts sum-free partitions, sum-full A237668.
%Y A367399 A366738 counts semi-sums of partitions, strict A366741.
%Y A367399 A367403 counts partitions without covering semi-sums, strict A367411.
%Y A367399 Triangles:
%Y A367399 A008284 counts partitions by length, strict A008289.
%Y A367399 A365541 counts subsets with a semi-sum k.
%Y A367399 A367404 counts partitions with a semi-sum k, strict A367405.
%Y A367399 Cf. A000700, A126796, A188431, A238628, A237113, A363225, A364272, A365658, A365918, A365925, A367410.
%K A367399 nonn
%O A367399 0,4
%A A367399 _Gus Wiseman_, Nov 19 2023