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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 July 15 10:49 EDT 2024. Contains 374332 sequences. (Running on oeis4.)