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A370925 Rectangular array, read by antidiagonals: row n consists of the numbers m whose ternary representation starts with 2 and has exactly n runs.

%I A370925 #7 Mar 15 2024 21:30:40
%S A370925 2,8,6,26,7,19,80,18,20,57,242,22,21,59,172,728,24,23,60,173,516,2186,
%T A370925 25,55,61,177,518,1549,6560,54,56,64,178,519,1550,4647,19682,67,58,65,
%U A370925 181,520,1554,4649,13942
%N A370925 Rectangular array, read by antidiagonals: row n consists of the numbers m whose ternary representation starts with 2 and has exactly n runs.
%C A370925 Every positive integer occurs in this array or A370924.
%e A370925 Corner:
%e A370925        2     8    26    80   242   728  2186
%e A370925        6     7    18    22    24    25    54
%e A370925       19    20    21    23    55    56    58
%e A370925       57    59    60    61    64    65    69
%e A370925      172   173   177   178   181   182   183
%e A370925      516   518   519   520   532   533   534
%e A370925     1549  1550  1554  1555  1558  1559  1560
%t A370925 d[n_] := First[IntegerDigits[n, 3]];
%t A370925 a[n_] := a[n] = Select[Range[30000],
%t A370925 d[#] == 2 && Length[Split[IntegerDigits[#, 3]]] == n &];
%t A370925 t[n_, k_] := a[n][[k]];
%t A370925 Grid[Table[t[n, k], {n, 1, 10}, {k, 1, 10}]] (* array *)
%t A370925 Table[t[n - k + 1, k], {n, 10}, {k, n, 1, -1}] // Flatten (* sequence *)
%Y A370925 Cf. A007089, A157671, A370893, A370924.
%K A370925 nonn,base,tabl
%O A370925 1,1
%A A370925 _Clark Kimberling_, Mar 13 2024