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 A229095 Numbers n such that sum_{i=1..n} i^tau(i) == 0 (mod n), where tau(i) = A000005(i), the number of divisors of i. 6
 1, 8, 9, 67, 72, 467, 801, 1071, 5141, 7193, 25688, 68488, 97768, 111816, 381061 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS EXAMPLE 1^tau(1) + 2^tau(2) + … + 8^tau(8) + 9^tau(9) = 1^1 + 2^2 + 3^2 + 4^3 + 5^2 + 6^4 + 7^2 + 8^4 + 9^3 = 6273 and 6273 / 9 = 697. MAPLE with(numtheory); P:=proc(q) local n, t; t:=0; for n from 1 to q do t:=t+n^tau(n); if t mod n=0 then print(n); fi; od; end: P(10^6); CROSSREFS Cf. A000005, A227427, A227429, A227502, A227848. Sequence in context: A025633 A249697 A038287 * A041140 A195940 A195991 Adjacent sequences:  A229092 A229093 A229094 * A229096 A229097 A229098 KEYWORD nonn AUTHOR Paolo P. Lava, Sep 13 2013 STATUS approved

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Last modified October 18 23:39 EDT 2019. Contains 328211 sequences. (Running on oeis4.)