A054012 - OEIS

A054012

Nonzero values of n read modulo (number of proper divisors of n).

2, 1, 1, 2, 2, 3, 1, 3, 1, 2, 3, 2, 2, 1, 2, 4, 2, 5, 4, 1, 3, 1, 2, 5, 1, 1, 5, 2, 3, 4, 2, 3, 3, 6, 2, 1, 2, 1, 8, 1, 1, 7, 1, 2, 4, 2, 1, 2, 1, 2, 8, 3, 4, 4, 4, 6, 1, 9, 5, 4, 2, 1, 1, 2, 1, 2, 1, 2, 4, 2, 5, 2, 4, 1, 2, 2, 3, 5, 8, 1, 2, 4, 1, 2, 2, 3, 7, 5, 3, 2, 2, 2, 6, 2, 4, 4, 1, 3, 1, 2, 1, 2, 6, 5, 1

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..105.

FORMULA

a(n) = A054011(A054009(n)).

MAPLE

with(numtheory):

[seq(`if`(i mod (tau(i)-1) <> 0, i mod (tau(i)-1), print( )), i=2..220)];

MATHEMATICA

Cases[Table[Mod[n, DivisorSigma[0, n]-1], {n, 2, 200}], Except[0]] (* Harvey P. Dale, Nov 12 2011 *)