A358715 a(n) is the number of distinct ways to cut an equilateral triangle with edges of size n into equilateral triangles with integer sides.

1, 2, 5, 26, 220, 3622, 105859, 5677789, 553715341, 98404068313, 31850967186980, 18779046566454536, 20167518569123722322, 39451359692134386945019

Offset: 1

Author

Craig Knecht and John Mason, Nov 28 2022

Keywords

• nonn
• more

Comments

In other words, the number of equilateral triangular tilings of an equilateral triangle, where rotations and reflections are considered distinct.

Examples

			a(3)=5 because of:
    /\      /\      /\      /\      /\
   /  \    /\/\    /  \    /\/\    /\/\
  /    \  /  \/\  /\/\/\  /\/  \  /\/\/\
		

Crossrefs

Cf. A045846, A097076, A358716.

Cf. A290820, A290821, A299705, A300001.

Extensions

a(10)-a(14) from Walter Trump, Dec 03 2022