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A239496
Number of (5,1)-separable partitions of n; see Comments.
4
0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 2, 2, 3, 3, 3, 3, 5, 5, 7, 8, 9, 10, 13, 14, 17, 20, 23, 26, 32, 35, 42, 48, 55, 63, 75, 83, 97, 111, 127, 144, 168, 188, 217, 246, 280, 317, 365, 409, 467, 528, 598, 674, 768, 861, 977, 1099, 1239, 1392, 1575, 1762, 1987
OFFSET
1,12
COMMENTS
Suppose that p is a partition of n into 2 or more parts and that h is a part of p. Then p is (h,0)-separable if there is an ordering x, h, x, h, ..., h, x of the parts of p, where each x represents any part of p except h. Here, the number of h's on the ends of the ordering is 0. Similarly, p is (h,1)-separable if there is an ordering x, h, x, h, ..., x, h, where the number of h's on the ends is 1; next, p is (h,2)-separable if there is an ordering h, x, h, ..., x, h. Finally, p is h-separable if it is (h,i)-separable for i = 0,1,2.
EXAMPLE
The (5,1)-separable partitions of 14 are 95, 3515, 2525, so that a(14) = 3.
MATHEMATICA
z = 70; Table[Count[IntegerPartitions[n], p_ /; 2 Count[p, 1] == Length[p]], {n, 1, z}] (* A008483 *)
Table[Count[IntegerPartitions[n], p_ /; 2 Count[p, 2] == Length[p]], {n, 1, z}] (* A239493 *)
Table[Count[IntegerPartitions[n], p_ /; 2 Count[p, 3] == Length[p]], {n, 1, z}] (* A239494 *)
Table[Count[IntegerPartitions[n], p_ /; 2 Count[p, 4] == Length[p]], {n, 1, z}] (* A239495 *)
Table[Count[IntegerPartitions[n], p_ /; 2 Count[p, 5] == Length[p]], {n, 1, z}] (* A239496 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Mar 20 2014
STATUS
approved