A346518 - OEIS

%I #11 Apr 07 2022 10:52:14

%S 1,2,5,16,53,202,826,3724,17939,93390,516125,3042412,18923139,

%T 124368810,857827458,6208594458,46937360868,370335617694,

%U 3039823038753,25928519847988,229285625745624,2099543718917418,19872430464012935,194203934113959970,1956736801957704866

%N Total number of partitions of all n-multisets {1,2,...,n-j,1,2,...,j} into distinct multisets for 0 <= j <= n.

%C Also total number of factorizations of Product_{i=1..n-j} prime(i) * Product_{i=1..j} prime(i) into distinct factors for 0 <= j <= n.

%H Alois P. Heinz, <a href="/A346518/b346518.txt">Table of n, a(n) for n = 0..576</a>

%F a(n) = Sum_{j=0..n} A045778(A002110(n-j)*A002110(j)).

%F a(n) = Sum_{j=0..n} A346517(n-j,j).

%p b:= proc(n) option remember; `if`(n=0, 1,

%p       add(b(n-j)*binomial(n-1, j-1), j=1..n))

%p     end:

%p A:= proc(n, k) option remember; `if`(n<k, A(k, n),

%p      `if`(k=0, b(n), (A(n+1, k-1)-add(A(n-k+j, j)

%p       *binomial(k-1, j), j=0..k-1)+A(n, k-1))/2))

%p     end:

%p a:= n-> add(A(n-j, j), j=0..n):

%p seq(a(n), n=0..24);

%t (* Q is A322770 *)

%t Q[m_, n_] := Q[m, n] = If[n == 0, BellB[m], (1/2) (Q[m + 2, n - 1] +

%t      Q[m + 1, n - 1] - Sum[Binomial[n - 1, k] Q[m, k], {k, 0, n - 1}])];

%t A[n_, k_] := Q[Abs[n - k], Min[n, k]];

%t a[n_] := Sum[A[n - j, j], {j, 0, n}];

%t Table[a[n], {n, 0, 24}] (* _Jean-François Alcover_, Apr 06 2022 *)

%Y Antidiagonal sums of A346517.

%Y Cf. A002110, A045778, A346490.

%K nonn

%O 0,2

%A _Alois P. Heinz_, Jul 21 2021