A267306 Earliest nonnegative increasing sequence having no 6-term subsequence with constant third differences.
0, 1, 2, 3, 4, 6, 7, 8, 9, 11, 12, 13, 14, 28, 29, 31, 32, 33, 34, 35, 37, 38, 40, 47, 79, 93, 94, 96, 97, 98, 99, 100, 102, 103, 105, 110, 116, 122, 128, 130, 140, 148, 266, 281, 296, 303, 304, 306, 308, 311, 313, 318, 324, 326, 327, 328, 330, 331, 332, 337
Offset: 1
Keywords
Crossrefs
Cf. A267307 (positive variant: starting with 1).
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.
Programs
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PARI
A267306(n, show=0, L=6, o=3, v=[0], D=v->v[2..-1]-v[1..-2])={ my(d, m); while( #v
1, ); #Set(d)>1||next(2), 2); break)); v[#v]} \\ M. F. Hasler, Jan 12 2016
Extensions
More terms from Jinyuan Wang, Jan 01 2021