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 A259478 Partition containment triangle. 19
 1, 2, 2, 3, 4, 3, 5, 8, 7, 5, 7, 12, 13, 12, 7, 11, 20, 23, 25, 19, 11, 15, 28, 35, 42, 39, 30, 15, 22, 42, 54, 70, 70, 66, 45, 22, 30, 58, 78, 105, 114, 119, 99, 67, 30, 42, 82, 112, 158, 178, 202, 186, 155, 97, 42, 56, 110, 154, 223, 262, 313, 314, 292, 226, 139, 56, 77, 152, 215, 319, 383, 479, 503, 511, 442, 336, 195, 77 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS T(n,k) counts pairs of partitions (lambda,mu) with Ferrers diagram of mu not extending beyond the diagram of lambda for all partitions lambda of size n and mu of size k <= n. First column and main diagonal both equal A000041 (partition numbers). This sequence counts (2,1)/(1) as different from (3,2,1)/(3,1) while their set-theoretic difference lambda - mu (their skew diagram) is the same. REFERENCES I. G. MacDonald: "Symmetric functions and Hall polynomials", Oxford University Press, 1979. Page 4. LINKS Alois P. Heinz, Rows n = 1..141, flattened Eric Weisstein's World of Mathematics, Ferrers Diagram Wikipedia, Ferrers diagram FORMULA Sum_{k=1..n} T(n,k) = A297388(n) - A000041(n). - Alois P. Heinz, Jan 10 2018 EXAMPLE T(3,2) = 4, the pairs of partitions are ((3)/(2)), ((2,1)/(2), ((2,1)/(1,1)), ((1,1,1)/(1,1)) and the diagrams are: x x 0 ,  x x , x 0 , x          0     x     x                      0 triangle begins: n=1;  1 n=2;  2  2 n=3;  3  4  3 n=4;  5  8  7  5 n=5;  7 12 13 12  7 n=6; 11 20 23 25 19 11 MAPLE b:= proc(n, i, t) option remember; expand(`if`(n=0 or i=1,       `if`(t=0, 1, add(x^j, j=0..n)), b(n, i-1, min(i-1, t))+        add(b(n-i, min(i, n-i), min(j, n-i))*x^j, j=0..t)))     end: T:= n-> (p-> seq(coeff(p, x, i), i=1..n))(b(n\$3)): seq(T(n), n=1..15);  # Alois P. Heinz, Jul 05 2015, revised Jan 10 2018 MATHEMATICA majorsweak[left_List, right_List]:=Block[{le1=Length[left], le2=Length[right]}, If[le2>le1||Min[Sign[left-PadRight[right, le1]]]<0, False, True]]; Table[Sum[ If[! majorsweak[\[Lambda], \[Mu]], 0, 1] , {\[Lambda], IntegerPartitions[n] }, {\[Mu], IntegerPartitions[m]}], {n, 7}, {m, n}] (* Second program: *) b[n_, m_, i_, j_, t_] := b[n, m, i, j, t] = If[m > n, 0, If[n == 0, 1, If[i < 1, 0, If[t && j > 0, b[n, m, i, j - 1, t], 0] + If[i > j, b[n, m, i - 1, j, False], 0] + If[i > n || j > m, 0, b[n - i, m - j, i, j, True]]]]]; T[n_, m_] :=  b[n, m, n, m, True]; Table[Table[T[n, m], {m, 1, n}], {n, 1, 14}] // Flatten (* Jean-François Alcover, Aug 27 2016, after Alois P. Heinz *) CROSSREFS Columns k=1-10 give: A000041, 2*A000065, A303853, A303854, A303855, A303856, A303857, A303858, A303859, A303860. Cf. A000070, A259479, A259480, A259481, A161492, A227309, A006958, A297388, A303851, A303852, A303861, A303862, A303863. Sequence in context: A096858 A037254 A316939 * A155706 A317533 A231227 Adjacent sequences:  A259475 A259476 A259477 * A259479 A259480 A259481 KEYWORD nonn,tabl AUTHOR Wouter Meeussen, Jun 28 2015 STATUS approved

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Last modified August 12 23:19 EDT 2020. Contains 336440 sequences. (Running on oeis4.)