A373300 Sum of successive integers in a row of length p(n) where p counts integer partitions.

1, 5, 15, 45, 105, 264, 555, 1221, 2445, 4935, 9324, 17941, 32522, 59400, 104808, 184569, 315711, 540540, 902335, 1504800, 2462724, 4014513, 6444425, 10316250, 16283707, 25610886, 39841865, 61720659, 94687230, 144731706, 219282679, 330996105, 495901413, 740046425

Offset

1,2

Comments

The length of each row is given by A000041.

As many sequences start like the positive integers, their row sums when disposed in this shape start with the same values.

Here is a sample list by A-number order of the sequences which are sufficiently close to A000027 to have the same row sums for at least 8 terms.

A069782, A088480, A090107, A090108, A090109, A115510, A115511, A130446, A131717, A132086, A153671, A167904, A296879, A296882, A296885, A296888, A296891, A296894, A296897, A296900, A296903, A296906, A303502, A317945, A335280, A361374.

Links

Table of n, a(n) for n=1..34.

Example

Let's put the list of integers in a triangle whose rows have length p(n), number of integer partitions of n.
.
    1 |  1
    5 |  2  3
   15 |  4  5  6
   45 |  7  8  9 10 11
  105 | 12 13 14 15 16 17 18
  264 | 19 20 21 22 23 24 25 26 27 28 29
  555 | 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
.
The sequence gives the row sums of this triangle.

Mathematica

Module[{s = 0},
 Table[s +=
   PartitionsP[n - 1]; (s + PartitionsP[n])*(s + PartitionsP[n] - 1)/2 -
   s*(s - 1)/2, {n, 1, 30}]]

Crossrefs

Cf. A000027, seen as a triangle with shape A000041.

Cf. A373301, the same principle, but starting from integer zero instead of 1.

Cf. A006003, row sums of the integers but for the linear triangle.

Sequence in context: A146632 A076103 A094283 * A158875 A022813 A000334

Adjacent sequences: A373297 A373298 A373299 * A373301 A373302 A373303

Keyword

nonn

Author

Olivier Gérard, May 31 2024

Status

approved