A138060 Triangle read by rows: row 1 = {1}; for n>1, row n is obtained from row n-1 by applying the morphism 1->1,2; 2->3; 3->4; 4->1.

1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4

Offset

1,3

Links

Table of n, a(n) for n=1..105.

Example

{1},
{1, 2},
{1, 2, 3},
{1, 2, 3, 4},
{1, 2, 3, 4, 1},
{1, 2, 3, 4, 1, 1, 2},
{1, 2, 3, 4, 1, 1, 2, 1, 2, 3},
{1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4},
{1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1},
{1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 2, 3, 4, 1, 1, 2},
{1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3}

Mathematica

SubstitutionSystem[{1 -> {1, 2}, 2 -> {3}, 3 -> {4}, 4 -> {1}}, {1}, 10] // Flatten (* Jean-François Alcover, Jul 01 2023 *)

Crossrefs

Row sums are A138289. Rows converge to A138297.

Cf. A103684.

Sequence in context: A368485 A113126 A348043 * A023121 A136261 A140756

Adjacent sequences: A138057 A138058 A138059 * A138061 A138062 A138063

Keyword

nonn,tabf,easy

Author

Roger L. Bagula, May 02 2008

Extensions

Edited by N. J. A. Sloane, May 06 2008

Status

approved