A106591 Irregular triangle read by rows generated by the morphism 1->456, 2->444, 3->555, 4->222, 5->333, 6->123 starting from a(0)=1.

1, 4, 5, 6, 2, 2, 2, 3, 3, 3, 1, 2, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 4, 5, 6, 4, 4, 4, 5, 5, 5, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 2, 3, 3, 3, 1, 2, 3, 2, 2

Offset

0,2

Links

Paolo Xausa, Table of n, a(n) for n = 0..9840 (rows 0..8 of triangle, flattened).

Curtis T. McMullen, Prym varieties and Teichmüller curves, Duke Math. J. 133(3) (2006), 569-590.

Example

Triangular form:
  1;
  4, 5, 6;
  2, 2, 2, 3, 3, 3, 1, 2, 3;
  4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 4, 5, 6, 4, 4, 4, 5, 5, 5;
  ...

Mathematica

SubstitutionSystem[{1 -> {4, 5, 6}, 2 -> {4, 4, 4}, 3 -> {5, 5, 5}, 4 -> {2, 2, 2}, 5 -> {3, 3, 3}, 6 -> {1, 2, 3}}, {1}, 4] (* Paolo Xausa, May 11 2026 *)

Crossrefs

Cf. A106592.

Sequence in context: A348355 A076087 A082486 * A106592 A106593 A276036

Adjacent sequences: A106588 A106589 A106590 * A106592 A106593 A106594

Keyword

nonn,tabf,easy

Author

Roger L. Bagula, May 10 2005

Extensions

Edited by Sean A. Irvine, May 07 2026

Status

approved