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A272082 Irregular triangle read by rows: strictly decreasing positive integer sequences in lexicographic order with the property that the sum of inverses is an integer. 4
1, 6, 3, 2, 6, 3, 2, 1, 12, 6, 4, 2, 12, 6, 4, 2, 1, 15, 10, 3, 2, 15, 10, 3, 2, 1, 15, 12, 10, 4, 2, 15, 12, 10, 4, 2, 1, 15, 12, 10, 6, 4, 3, 15, 12, 10, 6, 4, 3, 1, 18, 9, 3, 2, 18, 9, 3, 2, 1, 18, 12, 9, 4, 2, 18, 12, 9, 4, 2, 1, 18, 12, 9, 6, 4, 3, 18, 12 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Peter Kagey, Table of n, a(n) for n = 1..4039 (All rows with first term less than or equal to 30.)
EXAMPLE
First 8 rows:
[1] because 1/1 is an integer
[6, 3, 2] because 1/6 + 1/3 + 1/2 = 1.
[6, 3, 2, 1] because 1/6 + 1/3 + 1/2 + 1/1 = 2.
[12, 6, 4, 2] because 1/12 + 1/6 + 1/4 + 1/2 = 1.
[12, 6, 4, 2, 1] because 1/12 + 1/6 + 1/4 + 1/2 + 1/1 = 2.
[15, 10, 3, 2] because 1/15 + 1/10 + 1/3 + 1/2 = 1.
[15, 10, 3, 2, 1] because 1/15 + 1/10 + 1/3 + 1/2 + 1/1 = 2.
[15, 12, 10, 4, 2] because 1/15 + 1/12 + 1/10 + 1/4 + 1/2 = 1.
CROSSREFS
Sequence in context: A348694 A049605 A088395 * A283443 A266263 A177707
KEYWORD
nonn,tabf
AUTHOR
Peter Kagey, Apr 19 2016
STATUS
approved

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Last modified June 23 04:27 EDT 2024. Contains 373629 sequences. (Running on oeis4.)