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A244328 a(1) = a(2) = 0; for n >= 3: a(n) = floor((n*(n+1)/2) / antisigma(n)) = floor(A000217(n) / A024816(n)). 3

%I #8 Sep 08 2022 08:46:08

%S 0,0,3,3,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,

%T 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,

%U 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1

%N a(1) = a(2) = 0; for n >= 3: a(n) = floor((n*(n+1)/2) / antisigma(n)) = floor(A000217(n) / A024816(n)).

%H <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (1).

%F a(n) = 1 for n >= 7.

%F a(n) = A244327(n) - A244329(n) for n >= 7.

%e For n = 10; a(10) = floor(A000217(10) / A024816(10)) = floor(55 / 37) = 1.

%o (Magma) [Floor((n*(n+1)div 2) div ((n*(n+1)div 2)-SumOfDivisors(n))): n in [3..1000]]

%o (PARI) if(n>6,1,[0, 0, 3, 3, 1, 2][n]) \\ _Charles R Greathouse IV_, May 15 2015

%Y Cf. A000203, A000217, A024816, A244327, A244329.

%K nonn,easy

%O 1,3

%A _Jaroslav Krizek_, Jul 08 2014

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Last modified April 20 00:00 EDT 2024. Contains 371798 sequences. (Running on oeis4.)