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A280518 Number of increasing sequences of n positive integers with reciprocals adding up to an integer. 4
1, 0, 1, 7, 78, 2392, 248085, 151428144 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

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

EXAMPLE

a(4)=7 enumerates sequences: (1,2,3,6), (2,4,5,20), (2,4,6,12), (2,3,7,42), (2,3,8,24), (2,3,9,18), and (2,3,10,15).

CROSSREFS

Row sums of A280520.

Cf. A006585 (adding up to 1), A156871 (nondecreasing sequences), A280517 (ordered sequences).

Sequence in context: A186657 A079590 A202755 * A156714 A106110 A082992

Adjacent sequences:  A280515 A280516 A280517 * A280519 A280520 A280521

KEYWORD

nonn,hard,more

AUTHOR

Max Alekseyev, Jan 04 2017

STATUS

approved

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Last modified September 22 06:01 EDT 2021. Contains 347605 sequences. (Running on oeis4.)