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

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, 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, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1

Offset

1,3

Comments

Decimal expansion of 29809/900000. - Stefano Spezia, Sep 02 2024

Links

Table of n, a(n) for n=1..87.

Index entries for linear recurrences with constant coefficients, signature (1).

Formula

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

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

G.f.: x^3*(3 - 2*x^2 + x^3 - x^4)/(1 - x). - Elmo R. Oliveira, Aug 03 2024

E.g.f.: exp(x) - x - 1 + x^2*(x^4 + 60*x^2 + 240*x - 360)/720. - Stefano Spezia, Sep 02 2024

Example

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

Mathematica

PadRight[{0, 0, 3, 3, 1, 2}, 100, 1] (* Paolo Xausa, Sep 01 2024 *)

Prog

(Magma) [Floor((n*(n+1)div 2) div ((n*(n+1)div 2)-SumOfDivisors(n))): n in [3..1000]];
(PARI) if(n>6, 1, [0, 0, 3, 3, 1, 2][n]) \\ Charles R Greathouse IV, May 15 2015

Crossrefs

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

Sequence in context: A344390 A063421 A368339 * A073067 A003637 A317413

Adjacent sequences: A244325 A244326 A244327 * A244329 A244330 A244331

Keyword

nonn,easy

Author

Jaroslav Krizek, Jul 08 2014

Status

approved