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 A111407 a(n) = f(f(n+1)) - f(f(n)), where f(0) = 0 and f(m) = tau(m) = A000005(m) for m > 0. 2
 1, 1, 0, 0, 0, 1, -1, 1, -1, 1, -1, 2, -2, 1, 0, -1, 0, 2, -2, 2, -1, 0, -1, 2, -2, 1, 0, 1, -2, 2, -2, 2, -1, 0, 0, 0, -1, 1, 0, 1, -2, 2, -2, 2, 0, -1, -1, 2, -2, 2, -1, 1, -2, 2, -1, 1, -1, 0, -1, 4, -4, 1, 1, -2, 1, 1, -2, 2, -1, 1, -2, 4, -4, 1, 1, 0, -1, 1, -2, 2, -2, 1, -1, 4, -3, 0, 0, 1, -2, 4, -3, 1, -1, 0, 0, 3, -4, 2, 0, -1, -1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,12 LINKS Antti Karttunen, Table of n, a(n) for n = 0..20000 PROG (PARI) f = numdiv; a(n) = f(f(n+1)) - f(f(n)); concat([1], vector(166, n, a(n))) \\ Joerg Arndt, Jul 06 2013 (PARI) f(n) = if(!n, n, numdiv(n)); A111407(n) = f(f(n+1)) - f(f(n)); \\ Antti Karttunen, Oct 07 2017 CROSSREFS Cf. A000005, A111405. First differences of A010553. Sequence in context: A340594 A227193 A287397 * A084440 A179287 A016372 Adjacent sequences: A111404 A111405 A111406 * A111408 A111409 A111410 KEYWORD sign AUTHOR N. J. A. Sloane, Nov 12 2005 EXTENSIONS Description clarified by Antti Karttunen, Oct 07 2017 STATUS approved

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Last modified May 27 19:07 EDT 2023. Contains 362983 sequences. (Running on oeis4.)