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A183231 First of two complementary trees generated by the triangular numbers.  The second tree is A183232. 4
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified August 17 06:03 EDT 2017. Contains 290635 sequences.