

A275489


Most consecutive numbers that can be covered with arithmetic progressions of differences 2i+1, 1<=i<=n.


1



1, 2, 4, 6, 10, 13, 17, 22, 30, 38, 45, 53, 63, 74, 83, 96, 112, 128, 145
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OFFSET

1,2


COMMENTS

Erdos and Selfridge conjecture that there is no covering system whose moduli are distinct odd integers > 1. This is equivalent to saying that a(n) is finite for all n.


LINKS

Table of n, a(n) for n=1..19.
Wikipedia, Covering system.


EXAMPLE

[1,2,3,4] can be covered by the arithmetic progressions 3k+1, 5k+2 and 7k+3 but [1,2,3,4,5] can't be covered by three arithmetic progressions with differences 3, 5 and 7, so a(3) = 4.


CROSSREFS

Sequence in context: A233556 A087148 A297531 * A153817 A309616 A267452
Adjacent sequences: A275486 A275487 A275488 * A275490 A275491 A275492


KEYWORD

nonn,more


AUTHOR

Robert Israel, Jul 29 2016


STATUS

approved



