A225599 Triangle read by rows: T(n,k) = sum of all parts that start in the k-th column of the diagram of regions of the set of partitions of n.
1, 3, 1, 6, 1, 2, 12, 1, 4, 3, 20, 1, 4, 5, 5, 35, 1, 6, 8, 9, 7, 54, 1, 6, 10, 12, 11, 11, 86, 1, 8, 13, 20, 14, 19, 15, 128, 1, 8, 18, 23, 22, 25, 23, 22, 192, 1, 10, 21, 34, 30, 37, 29, 36, 30, 275, 1, 10, 26, 41, 41, 48, 41, 45, 46, 42, 399, 1, 12, 32, 56, 53, 72, 52, 67, 58, 66, 56
Offset: 1
Examples
For n = 5 and k = 3 the diagram of regions of the set of partitions of 5 contains three parts that start in the third column: two parts of size 1 and one part of size 2, therefore the sum of all parts that start in column 3 is 1 + 1 + 2 = 4, so T(5,3) = 4. . . Illustration of the parts . Diagram that start in column k: . for n=5 k=1 k=2 k=3 k=4 k=5 . _ _ _ _ _ _ _ _ _ _ . |_ _ _ | |_ _ _ _ _| _ _ . |_ _ _|_ | |_ _ _|_ |_ _| _ . |_ _ | | |_ _ _ _| _ _ |_| . |_ _|_ | | |_ _|_ |_ _| _ |_| . |_ _ | | | |_ _ _| _ |_| |_| . |_ | | | | |_ _| _ |_| |_| |_| . |_|_|_|_|_| |_| |_| |_| |_| |_| . k = 1 2 3 4 5 . The 5th row lists: 20 1 4 5 5 . Triangle begins: 1; 3, 1; 6, 1, 2; 12, 1, 4, 3; 20, 1, 4, 5, 5; 35, 1, 6, 8, 9, 7; 54, 1, 6, 10, 12, 11, 11; 86, 1, 8, 13, 20, 14, 19, 15; 128, 1, 8, 18, 23, 22, 25, 23, 22; 192, 1, 10, 21, 34, 30, 37, 29, 36, 30; 275, 1, 10, 26, 41, 41, 48, 41, 45, 46, 42; 399, 1, 12, 32, 56, 53, 72, 52, 67, 58, 66, 56;
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