A378286 a(n) = number of terms in row n of the array A378282.

1, 1, 1, 2, 2, 3, 4, 5, 7, 11, 16, 23, 35, 51, 75, 113, 168, 249, 374, 560, 840, 1262, 1896, 2844, 4270, 6405, 9607, 14421, 21633, 32449, 48676, 73027, 109546, 164334, 246528, 369784, 554686, 832046, 1248073, 1872168, 2808326, 4212710, 6319089, 9478842

Offset

1,4

Links

Table of n, a(n) for n=1..44.

Example

First eleven rows of array A378282:
1
1
2
1  1
1  2
2  1  1
1  1  2  1
1  2  1  1  2
2  1  1  2  1  2  2
1  1  2  1  2  2  1  2  2  1  1
1  2  1  1  2  1  1  2  2  1  2  2  1  1  2  2  1
a(11) = 16 = number of terms in row 11.

Mathematica

invRE[seq_, k_] := Flatten[Map[ConstantArray[#[[2]], #[[1]]] &,
    Partition[Riffle[seq, {k, 2 - Mod[k + 1, 2]}, {2, -1, 2}], 2]]];
row1 = {1}; rows = {row1};
col = PadRight[{}, 30, {1, 1, 2}](*112112112112112112...*);
Do[AppendTo[rows, invRE[Last[rows], col[[n]]]], {n, 2, Length[col]}]
rows // ColumnForm; (* A378282 *)
Map[Length, rows]  (* this sequence *)
(* Peter J. C. Moses, Nov 21 2024 *)

Crossrefs

Cf. A378282.

Sequence in context: A327662 A034395 A032232 * A175306 A359348 A021993

Adjacent sequences: A378283 A378284 A378285 * A378287 A378288 A378289

Keyword

nonn

Author

Clark Kimberling, Dec 20 2024

Status

approved