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A238098 Number of cubic polynomials with coefficients from {1..n} for which all three roots are integers. 2

%I

%S 0,0,1,1,2,3,4,5,7,8,10,12,13,15,19,21,23,25,27,30,34,36,39,44,46,49,

%T 54,57,60,64,67,72,76,79,85,91,92,95,100,106,109,115,117,122,129,132,

%U 136,147,150,154

%N Number of cubic polynomials with coefficients from {1..n} for which all three roots are integers.

%C A generalization of A006218 and A238096.

%D D. Andrica and E. J. Ionascu, On the number of polynomials with coefficients in [n], An. St. Univ. Ovidius Constanta, 2013, to appear.

%F a(n) = Sum_{k=1..n} floor(n/k)*A238097(k).

%K nonn

%O 1,5

%A _N. J. A. Sloane_, Feb 22 2014

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Last modified October 28 10:30 EDT 2021. Contains 348327 sequences. (Running on oeis4.)