This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A055884 #22 Feb 18 2023 16:01:55 %S A055884 1,1,2,1,2,3,1,4,4,5,1,4,8,7,7,1,6,12,16,12,11,1,6,17,25,28,19,15,1,8, %T A055884 22,43,49,48,30,22,1,8,30,58,87,88,77,45,30,1,10,36,87,134,167,151, %U A055884 122,67,42,1,10,45,113,207,270,296,247,185,97,56,1,12,54,155,295,448,510,507,394,278,139,77 %N A055884 Euler transform of partition triangle A008284. %C A055884 Number of multiset partitions of length-k integer partitions of n. - _Gus Wiseman_, Nov 09 2018 %H A055884 Alois P. Heinz, <a href="/A055884/b055884.txt">Rows n = 1..200, flattened</a> %H A055884 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a> %e A055884 From _Gus Wiseman_, Nov 09 2018: (Start) %e A055884 Triangle begins: %e A055884 1 %e A055884 1 2 %e A055884 1 2 3 %e A055884 1 4 4 5 %e A055884 1 4 8 7 7 %e A055884 1 6 12 16 12 11 %e A055884 1 6 17 25 28 19 15 %e A055884 1 8 22 43 49 48 30 22 %e A055884 1 8 30 58 87 88 77 45 30 %e A055884 ... %e A055884 The fifth row {1, 4, 8, 7, 7} counts the following multiset partitions: %e A055884 {{5}} {{1,4}} {{1,1,3}} {{1,1,1,2}} {{1,1,1,1,1}} %e A055884 {{2,3}} {{1,2,2}} {{1},{1,1,2}} {{1},{1,1,1,1}} %e A055884 {{1},{4}} {{1},{1,3}} {{1,1},{1,2}} {{1,1},{1,1,1}} %e A055884 {{2},{3}} {{1},{2,2}} {{2},{1,1,1}} {{1},{1},{1,1,1}} %e A055884 {{2},{1,2}} {{1},{1},{1,2}} {{1},{1,1},{1,1}} %e A055884 {{3},{1,1}} {{1},{2},{1,1}} {{1},{1},{1},{1,1}} %e A055884 {{1},{1},{3}} {{1},{1},{1},{2}} {{1},{1},{1},{1},{1}} %e A055884 {{1},{2},{2}} %e A055884 (End) %p A055884 h:= proc(n, i) option remember; expand(`if`(n=0, 1, %p A055884 `if`(i<1, 0, h(n, i-1)+x*h(n-i, min(n-i, i))))) %p A055884 end: %p A055884 g:= proc(n, i, j) option remember; expand(`if`(j=0, 1, `if`(i<0, 0, add( %p A055884 g(n, i-1, j-k)*x^(i*k)*binomial(coeff(h(n$2), x, i)+k-1, k), k=0..j)))) %p A055884 end: %p A055884 b:= proc(n, i) option remember; expand(`if`(n=0, 1, %p A055884 `if`(i<1, 0, add(b(n-i*j, i-1)*g(i$2, j), j=0..n/i)))) %p A055884 end: %p A055884 T:= (n, k)-> coeff(b(n$2), x, k): %p A055884 seq(seq(T(n,k), k=1..n), n=1..12); # _Alois P. Heinz_, Feb 17 2023 %t A055884 sps[{}]:={{}};sps[set:{i_,___}]:=Join@@Function[s,Prepend[#,s]&/@sps[Complement[set,s]]]/@Cases[Subsets[set],{i,___}]; %t A055884 mps[set_]:=Union[Sort[Sort/@(#/.x_Integer:>set[[x]])]&/@sps[Range[Length[set]]]]; %t A055884 Table[Length[Join@@mps/@IntegerPartitions[n,{k}]],{n,5},{k,n}] (* _Gus Wiseman_, Nov 09 2018 *) %Y A055884 Row sums give A001970. %Y A055884 Main diagonal gives A000041. %Y A055884 Columns k=1-2 give: A057427, A052928. %Y A055884 T(n+2,n+1) gives A000070. %Y A055884 T(2n,n) gives A360468. %Y A055884 Cf. A055885, A055886, A360742. %Y A055884 Cf. A000219, A007716, A008284, A255906, A317449, A317532, A317533, A320796, A320801, A320808. %K A055884 nonn,tabl %O A055884 1,3 %A A055884 _Christian G. Bower_, Jun 09 2000