A225859 Smallest k such that n numbers can be picked in {1,...,k} with no five terms in arithmetic progression.

1, 2, 3, 4, 6, 7, 8, 9, 11, 12, 13, 14, 16, 17, 18, 19, 24, 25, 27, 28, 29, 31, 33, 34, 36, 37, 38, 39, 41, 42, 43, 44, 49, 51, 52, 54, 56, 57, 58, 59, 61, 62, 63, 64, 66, 67, 68, 69, 76

Offset: 1

Author

Don Knuth, Aug 05 2013

Keywords

• nonn
• more

References

• Knuth, Donald E., Satisfiability, Fascicle 6, volume 4 of The Art of Computer Programming. Addison-Wesley, 2015, pages 135 and 190, Problem 31.

Links

• Samuel S. Wagstaff, Jr., On k-free sequences of integers, Math. Comp., 26 (1972), 767-771.

Crossrefs

This sequence is to A003004 as A065825 is to A003002.

Cf. A226066.