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 A175253 a(n) = characteristic function of numbers k such that A000203(m) = k has no solution for any m, where A000203(m) = sum of divisors of m. 2
 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) = characteristic function of numbers from A007369(n). a(n) = 1 if A000203(m) not equal to n for any m, else 0. a(n) = 1 for such n that A054973(n) = 0. a(n) = 0 for such n that A054973(n) >= 1. a(n) + A175192(n) = A000012(n). LINKS Jaroslav Krizek, Table of n, a(n) for n = 1..10000 MATHEMATICA seq[max_] := Module[{t = Table[0, {max}]}, t[[Complement[Range[max], Table[ DivisorSigma[1, n], {n, 1, max}]]]] = 1; t]; seq[100] (* Amiram Eldar, Mar 22 2024 *) CROSSREFS Cf. A074753, A202275, A202276, A175523, A007369, A007368, A007609. Sequence in context: A129185 A283683 A118605 * A163584 A353307 A286655 Adjacent sequences: A175250 A175251 A175252 * A175254 A175255 A175256 KEYWORD nonn AUTHOR Jaroslav Krizek, Mar 14 2010 EXTENSIONS More terms from Jaroslav Krizek, Dec 25 2011. STATUS approved

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Last modified September 18 06:58 EDT 2024. Contains 375996 sequences. (Running on oeis4.)