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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A032515 Sum of the integer part of 5/2-th roots of integers less than or equal to n. 4
0, 1, 2, 3, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 28, 31, 34, 37, 40, 43, 46, 49, 52, 55, 58, 61, 64, 67, 70, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125, 129, 133, 137, 141, 145, 149, 153, 157, 161, 165, 169, 174, 179, 184, 189, 194, 199 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..61.

FORMULA

a(0) = 0, a(n) = a(n - 1) + floor(n^(2/5)). - Alonso del Arte, Jun 18 2017

a(n) = (5/7)*n^(7/5) + O(n). - Charles R Greathouse IV, Jun 25 2017

EXAMPLE

1^(2/5) = 1.

2^(2/5) = 1.3195...

3^(2/5) = 1.5518...

4^(2/5) = 1.7411...

5^(2/5) = 1.90365...

6^(2/5) = 2.047672511...

Hence a(1) = 1, a(2) = 2, a(3) = 3, a(4) = 4, a(5) = 5, a(6) = 7.

MATHEMATICA

Accumulate[Table[Floor[n^(2/5)], {n, 0, 59}]] (* Alonso del Arte, Jun 13 2017 *)

PROG

(PARI) a(n)=sum(k=1, n, sqrtnint(k^2, 5)) \\ Charles R Greathouse IV, Jun 25 2017

CROSSREFS

Sequence in context: A004276 A033057 A092755 * A024926 A051532 A325461

Adjacent sequences:  A032512 A032513 A032514 * A032516 A032517 A032518

KEYWORD

nonn,easy

AUTHOR

Michel Tixier (tixier(AT)dyadel.net)

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 October 15 07:38 EDT 2019. Contains 328026 sequences. (Running on oeis4.)