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

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A115273 a(n) = floor(n/3)*(n mod 3). 10
0, 0, 0, 0, 1, 2, 0, 2, 4, 0, 3, 6, 0, 4, 8, 0, 5, 10, 0, 6, 12, 0, 7, 14, 0, 8, 16, 0, 9, 18, 0, 10, 20, 0, 11, 22, 0, 12, 24, 0, 13, 26, 0, 14, 28, 0, 15, 30, 0, 16, 32, 0, 17, 34, 0, 18, 36, 0, 19, 38, 0, 20, 40, 0, 21, 42, 0, 22, 44, 0, 23, 46, 0, 24, 48, 0, 25, 50, 0, 26, 52, 0, 27, 54, 0, 28, 56 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,6
COMMENTS
Three arithmetic progressions interlaced: a(1)=1,2,0 and d=a(n+1)-a(n)=1,2,0. Cf. A115274(n) = n+a(n), n=1,2,3,...
LINKS
FORMULA
a(3k+1) = k, a(3k+2) = 2k, a(3k+3) = 0, k=1, 2, ...
G.f.: x^4*(2*x+1) / ((x-1)^2*(x^2+x+1)^2). - Colin Barker, May 11 2015
MATHEMATICA
Table[Floor[n/3]*Mod[n, 3], {n, 0, 104}] \\ Extended to offset 0 by M. F. Hasler, May 11 2015
PROG
(PARI) a(n, b=3)=(n=divrem(n, b))[1]*n[2] \\ M. F. Hasler, May 10 2015
(Magma) [Floor(n/3)*(n mod 3): n in [0..100]]; // Vincenzo Librandi, May 11 2015
(Python)
from math import prod
def A115273(n): return prod(divmod(n, 3)) # Chai Wah Wu, Jan 19 2023
CROSSREFS
Cf. A115274.
Cf. A142150 (the base 2 analog), A257844, ..., A257850.
Sequence in context: A141660 A368500 A209699 * A194759 A209697 A126440
KEYWORD
nonn,easy
AUTHOR
Zak Seidov, Jan 18 2006
EXTENSIONS
a(0)-a(3) and cross-references added by M. F. Hasler, May 11 2015
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 June 23 20:00 EDT 2024. Contains 373653 sequences. (Running on oeis4.)