login
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.
1
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, 39335, 50820, 50852, 86357, 95586, 106331, 160418, 295806, 314853, 368358, 459825
OFFSET
1,2
COMMENTS
Presumably there are infinitely many such triples.
PROG
(C++) See Links section.
CROSSREFS
Cf. A005839.
Sequence in context: A115815 A372665 A275241 * A290398 A033895 A196876
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Jun 03 2002
EXTENSIONS
More terms from Rémy Sigrist, Mar 14 2023
STATUS
approved