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A054008 n read modulo (number of divisors of n). 3
0, 0, 1, 1, 1, 2, 1, 0, 0, 2, 1, 0, 1, 2, 3, 1, 1, 0, 1, 2, 1, 2, 1, 0, 1, 2, 3, 4, 1, 6, 1, 2, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 1, 2, 3, 2, 1, 8, 1, 2, 3, 4, 1, 6, 3, 0, 1, 2, 1, 0, 1, 2, 3, 1, 1, 2, 1, 2, 1, 6, 1, 0, 1, 2, 3, 4, 1, 6, 1, 0, 1, 2, 1, 0, 1, 2, 3, 0, 1, 6, 3, 2, 1, 2, 3, 0, 1, 2, 3, 1, 1, 6, 1, 0, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

a(n)=0 iff n is a refactorable number (cf. A033950). - Franz Vrabec, Oct 16 2005

a(n) = A049850(n) mod A000005(n). - Jaroslav Krizek, Nov 27 2013

a(A066708(n)) = n and a(m) < n for m < A066708(n). - Reinhard Zumkeller, Sep 17 2014

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = n mod tau(n).

MAPLE

[ seq( i mod tau(i), i=1..130) ];

MATHEMATICA

a[n_] := Mod[n, DivisorSigma[0, n]]; Array[a, 105] (* Jean-Fran├žois Alcover, Sep 19 2017 *)

PROG

(Haskell)

a054008 n = n `mod` a000005 n  -- Reinhard Zumkeller, Sep 17 2014

(PARI) a(n) = n % numdiv(n); \\ Michel Marcus, Sep 19 2017

CROSSREFS

Cf. A000005, A054009.

Sequence in context: A220354 A281188 A323439 * A125676 A291955 A291904

Adjacent sequences:  A054005 A054006 A054007 * A054009 A054010 A054011

KEYWORD

nonn

AUTHOR

Asher Auel (asher.auel(AT)reed.edu) Jan 12, 2000

STATUS

approved

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Last modified October 17 07:50 EDT 2019. Contains 328106 sequences. (Running on oeis4.)