A183231 First of two complementary trees generated by the triangular numbers. The second tree is A183232.

1, 4, 3, 19, 7, 13, 6, 229, 25, 43, 11, 118, 18, 34, 10, 26794, 250, 376, 32, 1033, 52, 89, 16, 7258, 133, 208, 24, 664, 42, 76, 15, 359026204, 27025, 31876, 272, 71629, 403, 593, 40, 536128, 1078, 1483, 62, 4184, 102, 169, 22, 26357428

Offset

1,2

Comments

Begin with the main tree A183079 generated by the triangular numbers:

......................1

......................2

.............3.................4

.........6.......5........10........7

.......21..9...15..8....55..14....28..11

Every n>2 is in the subtree from 3 or the subtree from 4.

Therefore, on subtracting 2 from all entries of those subtrees, we obtain complementary trees: A183231 and A183232.

Links

Table of n, a(n) for n=1..48.

Formula

See the formulas at A183079 and A183233.

Example

First three levels:
............1
.......4.........3
....19...7.....13..6

Crossrefs

Cf. A183079, A183232 (second tree), A183233.

Sequence in context: A276083 A161893 A192773 * A241358 A178417 A178628

Adjacent sequences: A183228 A183229 A183230 * A183232 A183233 A183234

Keyword

nonn,tabf

Author

Clark Kimberling, Jan 02 2011

Status

approved