A062896 Number of addition triangles with apex n (version 2).

1, 2, 2, 4, 4, 7, 7, 12, 12, 18, 19, 27, 28, 39, 41, 54, 58, 74, 78, 99, 106, 129, 139, 168, 179, 214, 229, 268, 289, 335, 357, 414, 443, 504, 540, 612, 653, 737, 786, 878, 938, 1045, 1111, 1234, 1313, 1444, 1539, 1692, 1795, 1965, 2082, 2273, 2414

Offset: 1

Author

Naohiro Nomoto, Feb 11 2002

Keywords

• easy
• nonn

Comments

An addition triangle has any set of positive numbers as base; other rows are formed by adding pairs of adjacent numbers.

Reversing the base does not count as a different triangle.

Examples

			For n = 5:
    5
   2,3     5     5
  1,1,2   4,1   2,3   5.
with four different bases, so a(5) = 4.
		

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..200

Crossrefs

See A062684 for version 1 (counts reversals).

Equivalent sequences with restrictions on rows: A337765 (weakly increasing), A337766 (strongly increasing).

Equivalent sequence where n is the sum of all numbers in the triangle: A337787.

Cf. A028307, A066411.

Extensions

Extended and edited by John W. Layman, Feb 14 2002