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 A075167 Number of edges in each rooted plane tree produced with the unranking algorithm presented in A075166, which is based on prime factorization. 10
 0, 1, 2, 2, 3, 3, 4, 3, 3, 4, 5, 4, 6, 5, 4, 3, 7, 4, 8, 5, 5, 6, 9, 4, 4, 7, 4, 6, 10, 5, 11, 4, 6, 8, 5, 5, 12, 9, 7, 5, 13, 6, 14, 7, 5, 10, 15, 5, 5, 5, 8, 8, 16, 5, 6, 6, 9, 11, 17, 6, 18, 12, 6, 4, 7, 7, 19, 9, 10, 6, 20, 5, 21, 13, 5, 10, 6, 8, 22, 6, 4, 14, 23, 7, 8, 15, 11, 7, 24, 6, 7, 11 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Each n occurs A000108(n) times in total. LINKS Antti Karttunen, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A106457(A106442(n)). - Antti Karttunen, May 09 2005 From Antti Karttunen, Jan 16 2015: (Start) a(1) = 0; for n>1: a(n) = a(A071178(n)) + (A061395(n) - A061395(A051119(n))) + A253783(A051119(n)). Other identities. For all n >= 2, a(n) = A055642(A075166(n))/2. [Half of the number of decimal digits in A075166(n).] For all n >= 2, a(n) = A029837(1+A075165(n))/2. [Half of the binary width of A075165(n).] For all n >= 1, a(n) = A000120(A075165(n)). [Thus also the binary weight of A075165(n), because half of the bits are zeros.] (End) PROG (Scheme, with memoization-macro definec) (definec (A075167 n) (if (= 1 n) 0 (+ (A075167 (A071178 n)) (- (A061395 n) (A061395 (A051119 n))) (A253783 (A051119 n))))) ;; Antti Karttunen, Jan 16 2015 CROSSREFS Permutation of A072643 and A106457. A253782 gives the positions where this sequence differs from A252464 (first time at n=16). Cf. A000108, A000120, A029837, A055642, A051119, A061395, A071178, A075165, A075166, A106442, A253783. Cf. also A106490. Sequence in context: A099053 A230697 A322163 * A253555 A252464 A269989 Adjacent sequences:  A075164 A075165 A075166 * A075168 A075169 A075170 KEYWORD nonn AUTHOR Antti Karttunen, Sep 13 2002 EXTENSIONS More terms from Antti Karttunen, May 09 2005 STATUS approved

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Last modified March 18 22:11 EDT 2019. Contains 321305 sequences. (Running on oeis4.)