OFFSET
1,3
COMMENTS
Generation n consists of 2^(n-1) increasing n-tuples that have maximal gapsize 2.
LINKS
Clark Kimberling, Table of n, a(n) for n = 1..4000
EXAMPLE
generation g(1) = (1);
g(2) = (1,2), (1,3);
g(3) = (1,2,3), (1,2,4), (1,3,4), (1,3,5);
g(4) = (1,2,3,4), (1,2,3,5), (1,2,4,5), (1,2,4,6), (1,3,4,5), (1,3,4,6), (1,3,5,6), (1,3,5,7).
MATHEMATICA
z = 5; t[n_] := t[n] = Join[{{First[#]}}, Rest[#]] &[Sort[Flatten[NestList[Map[Flatten, Transpose[Map[Flatten[#, 1] &, {{#, #}, {1 + Map[Last, #], 2 + Map[Last, #]}}]]] &, 1(*seed*), #], 1]] &[n(*iterations*)]]
Column[Table[t[n], {n, 1, z}]] (* 1st z generations *)
Flatten[t[6]] (* A255809, Peter J. C. Moses, Mar 05 2015 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Mar 09 2015
STATUS
approved