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A346603
The first of four solutions to a Monthly problem asking if there exist finite sequences 1 < a(1) < a(2) < ... < a(n) such that Sum_i 1/a(i) = 1 and gcd(a(i), a(i+1)) = 1 for 1 <= i < n.
3
3, 4, 5, 9, 22, 25, 99, 100
OFFSET
1,1
COMMENTS
There are probably a large number of such sequences, but it seems worthwhile putting these four examples on record. They were the only solutions submitted.
LINKS
Daniel Ullman, Proposer, Problem E3359, Amer. Math. Monthly, 98:2 (1991), 168.
CROSSREFS
KEYWORD
nonn,fini,full
AUTHOR
N. J. A. Sloane, Aug 06 2021
STATUS
approved