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 A264970 If A262686(n) = 0, a(n) = 0, otherwise a(n) = 1 + a(A262686(n)), where A262686(n) = largest number k such that k - d(k) = n, or 0 if no such number exists, and d(n) = the number of divisors of n (A000005). 4
 12, 2, 11, 2, 1, 1, 10, 0, 0, 3, 2, 2, 9, 0, 1, 5, 1, 4, 8, 0, 0, 3, 7, 2, 0, 0, 2, 1, 0, 1, 6, 6, 1, 0, 5, 5, 0, 0, 6, 4, 0, 1, 4, 0, 1, 3, 3, 2, 5, 0, 0, 1, 0, 2, 2, 0, 0, 1, 1, 4, 4, 3, 3, 0, 0, 2, 0, 0, 0, 1, 2, 3, 3, 2, 0, 0, 2, 1, 4, 0, 1, 1, 3, 3, 2, 0, 2, 2, 0, 4, 3, 1, 1, 3, 2, 5, 1, 4, 0, 2, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS a(n) = number of iterations of A262686 needed before zero is reached. In the context of tree (A263267) defined by edge-relation A049820(child) = parent, this is the number of hops we make before reaching one of the leaves (A045765), when we start from n and always select the largest child at each iteration. LINKS Antti Karttunen, Table of n, a(n) for n = 0..10000 FORMULA If A060990(n) = 0, a(n) = 0, otherwise a(n) = 1 + a(A262686(n)). Other identities. For all n >= 0: a(n) = A264971(n) - 1. PROG (Scheme, with memoization-macro definec) (definec (A264970 n) (cond ((A262686 n) => (lambda (lad) (if (zero? lad) 0 (+ 1 (A264970 lad))))))) CROSSREFS Cf. A000005, A049820, A060990, A262686, A263267. Cf. A045765 (positions of zeros). One less than A264971. Sequence in context: A322521 A099136 A215416 * A287205 A183729 A238718 Adjacent sequences: A264967 A264968 A264969 * A264971 A264972 A264973 KEYWORD nonn AUTHOR Antti Karttunen, Nov 29 2015 STATUS approved

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Last modified September 8 15:19 EDT 2024. Contains 375753 sequences. (Running on oeis4.)