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A090758
Numbers k which occur exactly twice in A001600.
1
5, 13, 15, 17, 19, 24, 29, 37, 44, 45, 46, 47, 61, 73, 75, 85, 86, 87, 99, 105, 107, 144, 145, 149, 171, 173, 186, 187, 197, 203, 205, 224, 245, 252, 270, 272, 276, 279, 282, 284
OFFSET
1,1
LINKS
EXAMPLE
k = 61 is a term because m*tau(m)/sigma(m) = 61 if and only if m = 2^30 * 61 * (2^31-1) or m = 2^60 * (2^61-1). - Jinyuan Wang, Mar 05 2020
CROSSREFS
Sequence in context: A174069 A020996 A090759 * A327922 A309812 A324909
KEYWORD
nonn,more
AUTHOR
R. K. Guy, Feb 08 2004
STATUS
approved