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 A160001 Number of partitions of n into distinct parts occurring in '3x+1'-trajectory starting with n. 2
 1, 1, 2, 1, 2, 4, 3, 1, 4, 3, 4, 9, 4, 8, 5, 1, 6, 18, 10, 5, 2, 13, 6, 25, 19, 10, 8, 41, 24, 14, 10, 1, 40, 19, 8, 138, 90, 55, 62, 7, 17, 3, 144, 63, 34, 16, 16, 43, 218, 148, 105, 22, 7, 39, 24, 323, 371, 150, 224, 54, 27, 40, 30, 1, 572, 444, 344, 71, 32, 19, 39, 1766, 52 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS R. Zumkeller, Table of n, a(n) for n = 1..100 Wikipedia, Collatz conjecture EXAMPLE 7-22-11-34-17-52-26-13-40-20-10-5-16-8-[4-2-1]*: {1,2,4,5,7} is the set of numbers <= n, occurring in this trajectory, therefore a(7) = #{7, 5+2, 4+2+1} = 3. PROG (Haskell) a160001 n = p (takeWhile (<= n) \$ sort \$ a070165_row n) n where    p _      0 = 1    p []     _ = 0    p (k:ks) m = if m < k then 0 else p ks (m - k) + p ks m -- Reinhard Zumkeller, Sep 01 2012 CROSSREFS Cf. A160000, A000009, A159999, A006370. Cf. A070165. Sequence in context: A256184 A120855 A193737 * A179750 A091173 A101897 Adjacent sequences:  A159998 A159999 A160000 * A160002 A160003 A160004 KEYWORD nonn AUTHOR Reinhard Zumkeller, May 11 2009 STATUS approved

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Last modified October 17 22:28 EDT 2019. Contains 328134 sequences. (Running on oeis4.)