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A344649 Triangle read by rows where T(n,k) is the number of strict integer partitions of 2n with reverse-alternating sum 2k.

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%I A344649 #13 Jun 09 2021 06:23:52
%S A344649 1,0,1,0,0,1,0,1,0,1,0,1,1,0,1,0,1,2,1,0,1,0,1,3,2,1,0,1,0,1,3,3,2,1,
%T A344649 0,1,0,1,4,4,3,2,1,0,1,0,1,5,6,4,3,2,1,0,1,0,1,7,7,6,4,3,2,1,0,1,0,1,
%U A344649 8,10,8,6,4,3,2,1,0,1
%N A344649 Triangle read by rows where T(n,k) is the number of strict integer partitions of 2n with reverse-alternating sum 2k.
%C A344649 The reverse-alternating sum of a partition (y_1,...,y_k) is Sum_i (-1)^(k-i) y_i. This is equal to (-1)^(m-1) times the number of odd parts in the conjugate partition, where m is the number of parts. So T(n,k) is the number of strict integer partitions of 2n into an odd number of parts whose conjugate has exactly 2k odd parts.
%C A344649 Also the number of reversed strict integer partitions of 2n with alternating sum 2k.
%e A344649 Triangle begins:
%e A344649    1
%e A344649    0   1
%e A344649    0   0   1
%e A344649    0   1   0   1
%e A344649    0   1   1   0   1
%e A344649    0   1   2   1   0   1
%e A344649    0   1   3   2   1   0   1
%e A344649    0   1   3   3   2   1   0   1
%e A344649    0   1   4   4   3   2   1   0   1
%e A344649    0   1   5   6   4   3   2   1   0   1
%e A344649    0   1   7   7   6   4   3   2   1   0   1
%e A344649    0   1   8  10   8   6   4   3   2   1   0   1
%e A344649    0   1  10  13  12   8   6   4   3   2   1   0   1
%e A344649    0   1  11  18  15  12   8   6   4   3   2   1   0   1
%e A344649    0   1  14  22  21  16  12   8   6   4   3   2   1   0   1
%e A344649    0   1  15  29  27  23  16  12   8   6   4   3   2   1   0   1
%e A344649 Row n = 8 counts the following partitions (empty columns indicated by dots):
%e A344649   .  (8,7,1)  (7,6,3)      (7,5,4)   (9,4,3)   (11,3,2)  (13,2,1)  .  (16)
%e A344649               (8,6,2)      (8,5,3)   (10,4,2)  (12,3,1)
%e A344649               (9,6,1)      (9,5,2)   (11,4,1)
%e A344649               (6,4,3,2,1)  (10,5,1)
%e A344649 Row n = 9 counts the following partitions (empty columns indicated by dots, A..I = 10..18):
%e A344649   .  981   873     765     954   B43   D32   F21   .  I
%e A344649            972     864     A53   C42   E31
%e A344649            A71     963     B52   D41
%e A344649            65421   A62     C51
%e A344649            75321   B61
%e A344649                    84321
%t A344649 sats[y_]:=Sum[(-1)^(i-Length[y])*y[[i]],{i,Length[y]}];
%t A344649 Table[Length[Select[IntegerPartitions[n],UnsameQ@@#&&sats[#]==k&]],{n,0,30,2},{k,0,n,2}]
%Y A344649 The non-reversed version is A152146.
%Y A344649 The non-reversed non-strict version is A239830.
%Y A344649 Column k = 2 is A343941.
%Y A344649 The non-strict version is A344610.
%Y A344649 Row sums are A344650.
%Y A344649 Right half of even-indexed rows of A344739.
%Y A344649 A000041 counts partitions of 2n with alternating sum 0, ranked by A000290.
%Y A344649 A067659 counts strict partitions of odd length.
%Y A344649 A103919 counts partitions by sum and alternating sum (reverse: A344612).
%Y A344649 A120452 counts partitions of 2n with reverse-alternating sum 2.
%Y A344649 A124754 gives alternating sum of standard compositions (reverse: A344618).
%Y A344649 A316524 is the alternating sum of the prime indices of n (reverse: A344616).
%Y A344649 A325534/A325535 count separable/inseparable partitions.
%Y A344649 A344604 counts wiggly compositions with twins.
%Y A344649 A344611 counts partitions of 2n with reverse-alternating sum >= 0.
%Y A344649 A344741 counts partitions of 2n with reverse-alternating sum -2.
%Y A344649 Cf. A000070, A000097, A003242, A006330, A027187, A114121, A116406, A239829, A344607, A344608, A344651, A344654.
%K A344649 nonn,tabl
%O A344649 0,18
%A A344649 _Gus Wiseman_, Jun 05 2021