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 A090387 Numerator of d(n)/n, where d(n) (A000005) is the number of divisors of n. 6
 1, 1, 2, 3, 2, 2, 2, 1, 1, 2, 2, 1, 2, 2, 4, 5, 2, 1, 2, 3, 4, 2, 2, 1, 3, 2, 4, 3, 2, 4, 2, 3, 4, 2, 4, 1, 2, 2, 4, 1, 2, 4, 2, 3, 2, 2, 2, 5, 3, 3, 4, 3, 2, 4, 4, 1, 4, 2, 2, 1, 2, 2, 2, 7, 4, 4, 2, 3, 4, 4, 2, 1, 2, 2, 2, 3, 4, 4, 2, 1, 5, 2, 2, 1, 4, 2, 4, 1, 2, 2, 4, 3, 4, 2, 4, 1, 2, 3, 2, 9, 2, 4, 2, 1, 8 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Values of n at which k first occurs, for k >= 1: 1, 3, 4, 15, 16, 175, 64, 105, 100, 567, 1024, 1925, 4096, 3645, 784, 945, 65536, ... - Robert G. Wilson v, Feb 04 2004. [Is this A136641? - Editors] LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 EXAMPLE a(6)=2 because the number of divisors of 6 is 4 and 4 divided by 6 equals 2/3, which has 2 as its numerator. MAPLE with(numtheory): seq(numer(tau(n)/n), n=1..105) ; # Zerinvary Lajos, Jun 04 2008 PROG (PARI) A090387(n) = numerator(numdiv(n)/n); \\ Antti Karttunen, Sep 25 2018 (Python) from math import gcd from sympy import divisor_count def A090387(n): return (d := divisor_count(n))//gcd(n, d) # Chai Wah Wu, Jun 20 2022 CROSSREFS Cf. A000005, A090395 (denominators), A136641. Sequence in context: A334052 A160570 A128830 * A030329 A300139 A300666 Adjacent sequences: A090384 A090385 A090386 * A090388 A090389 A090390 KEYWORD easy,frac,nonn AUTHOR Ivan_E_Mayle(AT)a_provider.com, Jan 31 2004 EXTENSIONS More terms from Robert G. Wilson v, Feb 04 2004 STATUS approved

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Last modified September 9 03:44 EDT 2024. Contains 375759 sequences. (Running on oeis4.)