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 A267307 Earliest positive increasing sequence having no 6-term subsequence with constant third differences. 2
 1, 2, 3, 4, 5, 7, 8, 9, 10, 12, 13, 14, 15, 29, 30, 32, 33, 34, 35, 36, 38, 39, 41, 48, 80, 94, 95, 97, 98, 99, 100, 101, 103, 104, 106, 111, 117, 123, 129, 131, 141, 149, 267, 282, 297, 304, 305, 307, 309, 312, 314, 319, 325, 327, 328, 329, 331, 332, 333, 338 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS PROG (PARI) A267307(n, show=0, L=6, o=3, v=[1], D=v->v[2..-1]-v[1..-2])={ my(d, m); while( #v1, ); #Set(d)>1||next(2), 2); break)); v[#v]} \\ M. F. Hasler, Jan 12 2016 CROSSREFS Cf. A267306 (nonnegative variant: starting with 0). No 3-term AP: A005836 (>=0), A003278 (>0); no 4-term AP: A240075 (>=0), A240555 (>0); no 5-term AP: A020654 (>=0), A020655 (>0); no 6-term AP: A020656 (>=0), A005838 (>0); no 7-term AP: A020657 (>=0), A020658 (>0); no 8-term AP: A020659 (>=0), A020660 (>0); no 9-term AP: A020661 (>=0), A020662 (>0); no 10-term AP: A020663 (>=0), A020664 (>0). Cf. A240075 and A240555 for sequences avoiding 4-term subsequences with constant second differences. Cf. A267300 and A267301 for sequences avoiding 5-term subsequences with constant second differences. Cf. A267302 and A267303 for sequences avoiding 6-term subsequences with constant second differences. Cf. A267304 and A267305 for sequences avoiding 7-term subsequences with constant second differences. Cf. A240556 and A240557 for sequences avoiding 5-term subsequences with constant third differences. Sequence in context: A047203 A080919 A267303 * A032974 A127565 A082186 Adjacent sequences:  A267304 A267305 A267306 * A267308 A267309 A267310 KEYWORD nonn AUTHOR M. F. Hasler, Jan 12 2016 EXTENSIONS More terms from Jinyuan Wang, Jan 08 2021 STATUS approved

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Last modified December 1 10:42 EST 2021. Contains 349427 sequences. (Running on oeis4.)