A062684 Number of addition triangles with apex n (version 1).

1, 2, 3, 5, 7, 10, 13, 18, 23, 29, 37, 46, 55, 68, 81, 96, 115, 135, 155, 183, 211, 241, 277, 317, 357, 407, 457, 513, 577, 645, 713, 799, 885, 977, 1079, 1191, 1305, 1438, 1571, 1717, 1875, 2048, 2221, 2423, 2625, 2840, 3077, 3333, 3589, 3876, 4163

Offset

1,2

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 counts as a different triangle.

Links

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

Example

For n = 5:
    5       5
   2,3     3,2     5     5     5     5
  1,1,2   2,1,1   4,1   1,4   2,3   3,2   5
with seven different bases, so a(5) = 7.

Crossrefs

Cf. A028307, A066411, see A062896 for version 2.

Sequence in context: A347647 A008766 A103232 * A341912 A033485 A026811

Adjacent sequences: A062681 A062682 A062683 * A062685 A062686 A062687

Keyword

easy,nonn

Author

Naohiro Nomoto, Feb 11 2002

Extensions

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

Status

approved