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A343375
a(n) is the least k such that Sum_{i=1..k} (i/prime(i))^n > 1.
0
2, 3, 6, 129, 107103, 19562634, 2433065908
OFFSET
1,1
EXAMPLE
a(2)=3 because 3 terms are needed for a sum > 1:
(1/2)^2 + (2/3)^2 < 1, but (1/2)^2 + (2/3)^2 + (3/5)^2 > 1.
a(3)=6 because 6 terms are needed for a sum > 1:
(1/2)^3 + (2/3)^3 + (3/5)^3 + (4/7)^3 + (5/11)^3 + (6/13)^3 > 1.
CROSSREFS
Cf. A000040.
Sequence in context: A018574 A018588 A018632 * A018646 A018665 A018673
KEYWORD
nonn,hard,more
AUTHOR
Alex Ratushnyak, Apr 12 2021
EXTENSIONS
a(7) from Daniel Suteu, May 04 2021
STATUS
approved