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A003002 Size of the largest subset of the numbers [1...n] which doesn't contain a 3-term arithmetic progression.
(Formerly M0275)
+0
7
1, 2, 2, 3, 4, 4, 4, 4, 5, 5, 6, 6, 7, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 11, 11, 11, 11, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 15, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 19, 20, 20, 20, 20, 20, 20, 20, 20, 21, 21, 21, 22, 22, 22, 22 (list; graph; listen)
OFFSET

1,2

COMMENT

These subsets have been called 3-free sequences.

Actually, more terms of this sequence can be found directly from A065825, because A003002(n) (this sequence) = the integer k such that A065825(k) <= n < A065825(k+1). [From R. Shreevatsa (shreevatsa.public(AT)gmail.com), Oct 18 2009]

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

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

CROSSREFS

Cf. A003003, A003004, A003005, A065825.

Sequence in context: A029130 A081611 A081228 this_sequence A087180 A029121 A161205

Adjacent sequences: A002999 A003000 A003001 this_sequence A003003 A003004 A003005

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

Extended from 53 terms to 80 terms, using a simple brute-force program with some pruning. R. Shreevatsa (shreevatsa.public(AT)gmail.com), Oct 18 2009

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Last modified December 4 12:48 EST 2009. Contains 170310 sequences.


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