A280517 Number of sequences of n positive integers with reciprocals adding up to an integer.

1, 2, 14, 263, 13462, 2104021, 1366427911, 6266456586228

Offset

1,2

Links

Table of n, a(n) for n=1..8.

Kassie Archer, Abigail Bishop, Alexander Diaz-Lopez, Luis David Garcia Puente, Darren Glass, Joel Louwsma, Arithmetical structures on bidents, arXiv:1903.01393 [math.CO], 2019.

Dilli Ram Chhetri, Namita Behera, Raj Bhawan Yadav, Arithmetical Structures On Fan Graphs, arXiv:2503.01913 [math.CO], 2025. See p. 17.

Crossrefs

Row sums of A280519.

Cf. A002967 (adding up to 1), A156871 (nondecreasing sequences), A280518 (increasing sequences).

Sequence in context: A156214 A370490 A187654 * A373222 A354511 A015197

Adjacent sequences: A280514 A280515 A280516 * A280518 A280519 A280520

Keyword

nonn,hard,more,changed

Author

Max Alekseyev, Jan 04 2017

Status

approved