A181854 - OEIS

%I #10 Jul 30 2013 04:06:26

%S 1,1,2,1,4,6,1,7,18,24,1,11,42,76,88,1,16,97,286,468,528,1,22,163,556,

%T 1050,1332,1392,1,29,317,1697,4942,8682,10716,11136,1,37,493,3209,

%U 11502,24770,36108,41016,41856

%N Triangle read by rows: Partial row sums of A181853(n,k)

%H Alois P. Heinz, <a href="/A181854/b181854.txt">Rows n = 0..25, flattened</a>

%e [0]   1

%e [1]   1    2

%e [2]   1    4     6

%e [3]   1    7    18    24

%e [4]   1   11    42    76     88

%e [5]   1   16    97   286    468    528

%e [6]   1   22   163   556   1050   1332   1392

%p with(combstruct):

%p a181854_row := proc(n) local k,L,l,R,comb;

%p R := NULL; L := 0;

%p for k from 0 to n do

%p    comb := iterstructs(Combination(n),size=k):

%p    while not finished(comb) do

%p       l := nextstruct(comb);

%p       L := L + ilcm(op(l));

%p    od;

%p    R := R,L;

%p od;

%p R end:

%t t[_, 0] = 1; t[n_, k_] := Sum[LCM @@ c, {c, Subsets[Range[n], {k}]}]; row[n_] := Table[t[n, k], {k, 0, n}] // Accumulate; Table[row[n], {n, 0, 8}] // Flatten (* _Jean-François Alcover_, Jul 30 2013 *)

%Y Cf. A096179, A181853.

%K nonn,tabl

%O 0,3

%A _Peter Luschny_, Dec 06 2010