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 A054015 a(n) is Chowla function of n read modulo (number of proper divisors of n), a(1) = 0 by convention. 5
 0, 0, 0, 0, 0, 2, 0, 0, 1, 1, 0, 0, 0, 0, 2, 2, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 2, 0, 6, 0, 0, 2, 1, 0, 6, 0, 0, 1, 0, 0, 4, 0, 4, 2, 1, 0, 3, 1, 2, 2, 0, 0, 2, 1, 0, 1, 1, 0, 8, 0, 0, 0, 2, 0, 0, 0, 2, 2, 3, 0, 1, 0, 0, 3, 3, 0, 5, 0, 6, 3, 1, 0, 7, 1, 0, 2, 0, 0, 0, 2, 0, 1, 1, 0, 1, 0, 2, 1, 4, 0, 1, 0, 0, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 COMMENTS Chowla's function (A048050) = sum of divisors of n except 1 and n. LINKS Antti Karttunen, Table of n, a(n) for n = 1..16384 FORMULA a(1) = 0; for n > 1, a(n) = A048050(n) mod A032741(n). MAPLE with(numtheory): [seq((sigma(i)-i-1) mod (tau(i)-1), i=2..120); #i>1 PROG (PARI) A054015(n) = if(1==n, 0, ((sigma(n)-n-1) % (numdiv(n)-1))); \\ Antti Karttunen, Oct 20 2017 CROSSREFS Cf. A032741, A048050, A054013, A054014. Sequence in context: A226350 A112609 A134363 * A056137 A332602 A306383 Adjacent sequences:  A054012 A054013 A054014 * A054016 A054017 A054018 KEYWORD nonn AUTHOR Asher Auel (asher.auel(AT)reed.edu), Jan 17 2000 EXTENSIONS Description clarified by Antti Karttunen, Oct 20 2017 STATUS approved

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Last modified January 17 23:51 EST 2022. Contains 350410 sequences. (Running on oeis4.)