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

Author

Max Alekseyev, Jan 04 2017

Keywords

• nonn
• hard
• more

Links

• 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).