login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A239831 Floor(7n^2/2) + floor(5n/2) + floor(3n/7). 1
5, 19, 39, 67, 101, 143, 191, 247, 308, 379, 454, 539, 628, 727, 830, 942, 1060, 1186, 1318, 1458, 1604, 1758, 1917, 2086, 2259, 2442, 2629, 2826, 3027, 3237, 3453, 3677, 3907, 4145, 4389, 4641, 4898, 5165, 5436, 5717, 6002, 6297, 6596, 6904, 7218, 7540 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

This is a quadratic sequence.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Wolfram Alpha, Table of floor(7n^2/2) + floor(5n/2) + floor(3n/7).

Index entries for linear recurrences with constant coefficients, signature (1,1,-1,0,0,0,1,-1,-1,1).

FORMULA

a(n) = (n(7n + 5) + (-1)^n - 1)/2 + A132270(3n + 1). [Bruno Berselli, Mar 28 2014]

a(n) = +a(n-1) +a(n-2) -a(n-3) +a(n-7) -a(n-8) -a(n-9) +a(n-10). [Bruno Berselli, Mar 28 2014]

EXAMPLE

For n=3, a(3) = floor(7*3^2/2) + floor(5*3/2) + floor(3*3/7) = 39.

MAPLE

A239831:=n->floor(7*n^2/2) + floor(5*n/2) + floor(3*n/7); seq(A239831(n), n=1..50); # Wesley Ivan Hurt, Mar 28 2014

MATHEMATICA

Table[Floor[7 n^2/2] + Floor[5 n/2] + Floor[3 n/7], {n, 50}] (* Bruno Berselli, Mar 28 2014 *)

PROG

(Magma) [Floor(7*n^2/2) + Floor(5*n/2) + Floor(3*n/7): n in [1..50]]; // Vincenzo Librandi, Mar 29 2014

CROSSREFS

Sequence in context: A257929 A254060 A129828 * A146600 A262997 A031379

Adjacent sequences: A239828 A239829 A239830 * A239832 A239833 A239834

KEYWORD

nonn,easy

AUTHOR

Katherine Guo, Mar 27 2014

EXTENSIONS

More terms from Bruno Berselli, Mar 28 2014

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 27 19:48 EST 2022. Contains 358406 sequences. (Running on oeis4.)