A344867 - OEIS

A344867

a(n) = n * Sum_{d|n} floor(sqrt(d)) / d.

1, 3, 4, 8, 7, 13, 9, 18, 15, 22, 14, 35, 16, 28, 29, 40, 21, 49, 23, 58, 38, 43, 27, 80, 40, 50, 50, 75, 34, 97, 36, 85, 58, 64, 64, 131, 43, 71, 67, 132, 47, 126, 49, 114, 108, 83, 53, 178, 70, 127, 87, 133, 60, 164, 99, 171, 95, 104, 66, 258, 68, 110, 142, 178, 114, 191, 75

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..67.

EXAMPLE

a(6) = 6 * Sum_{d|6} floor(sqrt(d)) / d = 6 * (floor(sqrt(1))/1 + floor(sqrt(2))/2 + floor(sqrt(3))/3 + floor(sqrt(6))/6) = 6 * (1 + 1/2 + 1/3 + 2/6) = 13.

MATHEMATICA

Table[n*Sum[Floor[Sqrt[k]] (1 - Ceiling[n/k] + Floor[n/k])/k, {k, n}], {n, 100}]

CROSSREFS

Cf. A344460.

Sequence in context: A019972 A064406 A299068 * A049826 A310014 A310015

Adjacent sequences: A344864 A344865 A344866 * A344868 A344869 A344870

KEYWORD

nonn

AUTHOR

Wesley Ivan Hurt, May 31 2021

STATUS

approved