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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.
2
2, 8, 6, 26, 7, 19, 80, 18, 20, 57, 242, 22, 21, 59, 172, 728, 24, 23, 60, 173, 516, 2186, 25, 55, 61, 177, 518, 1549, 6560, 54, 56, 64, 178, 519, 1550, 4647, 19682, 67, 58, 65, 181, 520, 1554, 4649, 13942
OFFSET
1,1
COMMENTS
Every positive integer occurs in this array or A370924.
EXAMPLE
Corner:
2 8 26 80 242 728 2186
6 7 18 22 24 25 54
19 20 21 23 55 56 58
57 59 60 61 64 65 69
172 173 177 178 181 182 183
516 518 519 520 532 533 534
1549 1550 1554 1555 1558 1559 1560
MATHEMATICA
d[n_] := First[IntegerDigits[n, 3]];
a[n_] := a[n] = Select[Range[30000],
d[#] == 2 && Length[Split[IntegerDigits[#, 3]]] == n &];
t[n_, k_] := a[n][[k]];
Grid[Table[t[n, k], {n, 1, 10}, {k, 1, 10}]] (* array *)
Table[t[n - k + 1, k], {n, 10}, {k, n, 1, -1}] // Flatten (* sequence *)
CROSSREFS
KEYWORD
nonn,base,tabl
AUTHOR
Clark Kimberling, Mar 13 2024
STATUS
approved