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 A175192 a(n) = characteristic function of numbers k such that A000203(m) = k has solution, where A000203(m) = sums of divisors of m. 7
 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) = 1 if A000203(m) = n for some m, else 0. a(n) = 1 for n such that A054973(n) >= 1. a(n) = 0 for n such that A054973(n) = 0. LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 MATHEMATICA nn = 200; t = Union[Select[DivisorSigma[1, Range[nn]], # <= nn &]]; t2 = Table[0, {200}]; t2[[t]] = 1; t2 (* T. D. Noe, Jan 24 2012 *) PROG (PARI) up_to = 65537 v175192 = vector(up_to); for(k=1, up_to, t=sigma(k); if(t<=up_to, v175192[t] = 1)); \\ See also code in A054973. write_to_bfile(start_offset, vec, bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); } write_to_bfile(1, v175192, "b175192_upto65537.txt"); \\ Antti Karttunen, Oct 20 2017 CROSSREFS Characteristic function of A002191. Cf. A000203, A054973. Sequence in context: A260192 A057078 A127245 * A088150 A117567 A307183 Adjacent sequences:  A175189 A175190 A175191 * A175193 A175194 A175195 KEYWORD nonn AUTHOR Jaroslav Krizek, Mar 01 2010 EXTENSIONS More terms from Antti Karttunen, Oct 20 2017 STATUS approved

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Last modified September 30 20:19 EDT 2020. Contains 337440 sequences. (Running on oeis4.)