A181843 Triangle read by rows: Partial row sums of A181842

1, 1, 3, 1, 3, 6, 1, 3, 8, 12, 1, 3, 8, 18, 23, 1, 3, 8, 20, 32, 38, 1, 3, 8, 20, 38, 66, 73, 1, 3, 8, 20, 40, 78, 110, 118, 1, 3, 8, 20, 40, 84, 141, 189, 198, 1, 3, 8, 20, 40, 86, 153, 253, 308, 318, 1, 3, 8, 20, 40, 86, 159, 287, 409, 519, 530, 1, 3, 8, 20, 40, 86, 161, 299, 476, 728, 807, 819

Offset

1,3

Links

Table of n, a(n) for n=1..78.

Example

[1]   1
[2]   1   3
[3]   1   3   6
[4]   1   3   8   12
[5]   1   3   8   18   23
[6]   1   3   8   20   32   38
[7]   1   3   8   20   38   66   73

Maple

with(combstruct):
a181843_row := proc(n) local k, L, l, R, part;
R := NULL; L := 0;
for k from 1 to n do
   part := iterstructs(Partition(n), size=n-k+1):
   while not finished(part) do
      l := nextstruct(part);
      L := L + ilcm(op(l));
   od;
   R := R, L;
od;
R end:

Mathematica

t[n_, k_] := LCM @@@ IntegerPartitions[n, {n - k + 1}] // Total; row[n_] := Table[t[n, k], {k, 1, n}] // Accumulate; Table[row[n], {n, 1, 12}] // Flatten (* Jean-François Alcover, Jul 26 2013 *)

Crossrefs

Cf. A181842, A181844.

Sequence in context: A049324 A356444 A256095 * A131111 A336574 A128549

Adjacent sequences: A181840 A181841 A181842 * A181844 A181845 A181846

Keyword

nonn,tabl

Author

Peter Luschny, Dec 07 2010

Extensions

Terms from an erroneous copy and paste transfer corrected.

More terms from Jean-François Alcover, Jul 26 2013

Status

approved