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A339629 Number of compositions (ordered partitions) of n into distinct parts such that the sum of reciprocals of parts is 1. 2
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 16 01:55 EDT 2021. Contains 343937 sequences. (Running on oeis4.)