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A071711 Let s(k) denote the k-th term of an integer sequence such that s(0)=0 and s(i) for all i>0 is the least natural number such that no four elements of {s(0),..,s(i)} are in arithmetic progression. Then it appears that there are many set of 3 consecutive integers in s(k). Sequence gives the smallest element in those triples. 0
0, 7, 14, 28, 48, 55, 64, 86, 108, 168, 286, 371, 471, 633, 760, 982, 1032, 1136, 1261, 1600, 1739, 1788, 1822, 1848, 3832, 4225, 5504, 7729, 8062, 9229, 10110, 21977, 27953 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Presumably there are infinitely many such triples.

LINKS

Table of n, a(n) for n=1..33.

K. S. Brown, Sequences With No Arithmetic Progressions

CROSSREFS

Sequence in context: A158204 A115815 A275241 * A290398 A033895 A196876

Adjacent sequences:  A071708 A071709 A071710 * A071712 A071713 A071714

KEYWORD

nonn,more

AUTHOR

Benoit Cloitre, Jun 03 2002

STATUS

approved

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Last modified October 21 18:36 EDT 2021. Contains 348155 sequences. (Running on oeis4.)