A339629 Number of compositions (ordered partitions) of n into distinct parts such that the sum of reciprocals of parts is 1.

0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 24, 0, 0, 0, 0, 0, 24, 24, 24, 0, 0, 0, 0, 24, 120, 0, 0, 0, 0, 120, 0, 240, 0, 0, 0, 0, 840, 0, 720, 120, 24, 120, 0, 1440, 0, 720, 720, 120, 840, 0, 2280, 720, 960, 1080, 0, 840, 0, 11760, 0, 5040, 1440, 720

Offset

0,12

Comments

Also the number of ordered ways to express 1 as the sum of distinct unit fractions such that the sum of the denominators is n.

Links

Table of n, a(n) for n=0..75.

Index entries for sequences related to compositions

Index entries for sequences related to Egyptian fractions

Example

a(11) = 6 because we have 2 + 3 + 6 = 2 + 6 + 3 = 3 + 2 + 6 = 3 + 6 + 2 = 6 + 2 + 3 = 6 + 3 + 2 = 11 and 1/2 + 1/3 + 1/6 = 1.

Crossrefs

Cf. A051907, A051908, A058360, A339627, A339628.

Sequence in context: A186685 A341882 A307382 * A331428 A323487 A173453

Adjacent sequences: A339626 A339627 A339628 * A339630 A339631 A339632

Keyword

nonn

Author

Ilya Gutkovskiy, Dec 10 2020

Status

approved