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 A353361 Number of divisors d of n for which A156552(d) is not a multiple of 3. 4
 0, 1, 1, 1, 1, 3, 1, 2, 1, 2, 1, 4, 1, 3, 3, 2, 1, 4, 1, 3, 2, 2, 1, 6, 1, 3, 2, 4, 1, 5, 1, 3, 3, 2, 3, 5, 1, 3, 2, 4, 1, 6, 1, 3, 4, 2, 1, 7, 1, 3, 3, 4, 1, 6, 2, 6, 2, 3, 1, 8, 1, 2, 3, 3, 3, 5, 1, 3, 3, 6, 1, 8, 1, 3, 4, 4, 3, 6, 1, 5, 2, 2, 1, 8, 2, 3, 2, 4, 1, 7, 2, 3, 3, 2, 3, 9, 1, 4, 4, 4, 1, 5, 1, 6, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 Index entries for sequences computed from indices in prime factorization FORMULA a(n) = Sum_{d|n} (1-A353269(d)). a(n) = A000005(n) - A353362(n). a(p) = 1 for all primes p. a(n) = a(A003961(n)) = a(A348717(n)), for all n >= 1. PROG (PARI) A156552(n) = { my(f = factor(n), p, p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res }; A353269(n) = (!(A156552(n)%3)); A353361(n) = sumdiv(n, d, !A353269(d)); CROSSREFS Cf. A000005, A003961, A156552, A348717, A353269, A353350, A353362. Cf. also A353351. Sequence in context: A271418 A230500 A010281 * A298421 A080131 A319956 Adjacent sequences: A353358 A353359 A353360 * A353362 A353363 A353364 KEYWORD nonn AUTHOR Antti Karttunen, Apr 15 2022 STATUS approved

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Last modified February 25 00:32 EST 2024. Contains 370308 sequences. (Running on oeis4.)