login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A174724 Sum_{k=1..n} Floor((k + 3*sqrt(k))/k). 0
4, 7, 9, 11, 13, 15, 17, 19, 21, 22, 23, 24, 25, 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, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..65.

Index entries for linear recurrences with constant coefficients, signature (2,-1).

FORMULA

(k+3*sqrt(k)) / k > = 1, (k+3*sqrt(k)) / k < 2 <=> k >=10, a(n) = 4 if n=1, a(n) = 2n + 3 if 2 <= n <= 9, a(n) = n + 12 if n>=10.

MAPLE

for n from 1 to 100 do: s:=0: for k from 1 to n do: s:=s+floor((k+3*sqrt(k))/k) : od:print(s):od:

PROG

(PARI) a(n)=if(n>8, n+12, 2*n+3-(n==1)) \\ Charles R Greathouse IV, Oct 27 2011

CROSSREFS

Sequence in context: A159619 A272454 A207017 * A267873 A310943 A310944

Adjacent sequences:  A174721 A174722 A174723 * A174725 A174726 A174727

KEYWORD

nonn,easy

AUTHOR

Michel Lagneau, Mar 28 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 12 22:06 EST 2019. Contains 329963 sequences. (Running on oeis4.)