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A003004 Size of the largest subset of the numbers [1...n] which does not contain a 5-term arithmetic progression.
(Formerly M0451)
+0
5
1, 2, 3, 4, 4, 5, 6, 7, 8, 8, 9, 10, 11, 12, 12, 13, 14, 15, 16, 16, 16, 16, 16, 17, 18, 18, 19, 20, 21, 21, 22, 22, 23, 24, 24, 25, 26, 27, 28, 28, 29, 30, 31, 32, 32, 32, 32, 32, 33, 33 (list; graph; listen)
OFFSET

1,2

COMMENT

These subsets have been called 5-free sequences.

The g.f. (z+1)*(1+z**2)/(z**4+z**3+z**2+z+1)/(z-1)**2 conjectured by S. Plouffe in his 1992 dissertation is wrong.

REFERENCES

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

LINKS

S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

CROSSREFS

Cf. A003002, A003003, A003005, A065825.

Adjacent sequences: A003001 A003002 A003003 this_sequence A003005 A003006 A003007

Sequence in context: A006162 A036701 A053756 this_sequence A120507 A090223 A109401

KEYWORD

nonn

AUTHOR

njas

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Last modified January 7 17:16 EST 2009. Contains 152824 sequences.


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