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A238401 Floor(sum(i/(i+1)),i=1..n). 1
0, 0, 1, 1, 2, 3, 4, 5, 6, 7, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

The first numbers which appear twice in the sequence are 0, 1, 7, 26, 77, 220, 608, 1665, 4540, 12356, 33605, 91367, 248383, 675199,... - Giovanni Resta, Feb 26 2014

These numbers appear at roughly exp(n - gamma). - Charles R Greathouse IV, Feb 26 2014

LINKS

Giovanni Resta, Table of n, a(n) for n = 0..1000

FORMULA

a(n) = n - log n + O(1). - Charles R Greathouse IV, Feb 26 2014

EXAMPLE

a(3) = floor(0/1 + 1/2 + 2/3 + 3/4) = floor(1.91666...) = 1.

PROG

(JavaScript)

c=0;

for (i=1; i<50; i++) {

c+=i/(i+1);

document.write(Math.floor(c)+", ");

}

(PARI) a(n)=n-ceil(sum(i=2, n, 1./i)) \\ Charles R Greathouse IV, Feb 26 2014

CROSSREFS

Cf. A055980, A001008, A002805.

Sequence in context: A228298 A309082 A124808 * A017862 A265539 A254926

Adjacent sequences:  A238398 A238399 A238400 * A238402 A238403 A238404

KEYWORD

nonn

AUTHOR

Jon Perry, Feb 26 2014

EXTENSIONS

a(50)-a(67) from Giovanni Resta, Feb 26 2014

STATUS

approved

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Last modified October 18 07:19 EDT 2019. Contains 328146 sequences. (Running on oeis4.)