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 A296084 a(1) = 0 and for n > 1, a(n) = 1 if tau(n)-1 divides sigma(n)-1, 0 otherwise. Here tau = A000005, sigma = A000203. 5
 0, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1 COMMENTS Also number of numbers of the form i*n with 1 <= i <= n and tau(i*n) = 3 (equivalently, i*n is the square of a prime). - N. J. A. Sloane, Nov 11 2020 LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 FORMULA a(n) = 1 iff A296082(n) = 1. MATHEMATICA Join[{0}, Table[If[Divisible[DivisorSigma[1, n]-1, DivisorSigma[0, n]-1], 1, 0], {n, 2, 120}]] (* Harvey P. Dale, Dec 15 2018 *) PROG (PARI) A296084(n) = if(1==n, 0, !((sigma(n)-1)%(numdiv(n)-1))); CROSSREFS Cf. A000005, A000203, A032741, A039653, A296082. Characteristic function of A284288. Sequence in context: A100656 A285274 A189081 * A302777 A324828 A053867 Adjacent sequences:  A296081 A296082 A296083 * A296085 A296086 A296087 KEYWORD nonn AUTHOR Antti Karttunen, Dec 05 2017 STATUS approved

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Last modified July 30 19:33 EDT 2021. Contains 346359 sequences. (Running on oeis4.)