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

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A039912 Triangle related to number of compositions of n into relatively prime summands. 1
1, 1, -2, 1, -3, 4, 1, -4, 6, -8, 1, -5, 10, -9, 16, 1, -6, 15, -20, 9, -32, 1, -7, 21, -35, 36, 0, 64, 1, -8, 28, -56, 70, -64, -27, -128, 1, -9, 36, -84, 126, -125, 120, 81, 256, 1, -10, 45, -120, 210, -252, 200, -240, -162, -512, 1, -11, 55, -165, 330, -462, 463, -275, 496, 243, 1024, 1, -12, 66, -220, 495, -792, 924 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

2,3

LINKS

Table of n, a(n) for n=2..74.

H. W. Gould, Binomial coefficients, the bracket function and compositions with relatively prime summands, Fib. Quart. 2 (1964), 2.

EXAMPLE

Triangle begins:

  1;

  1, -2;

  1, -3,  4;

  1, -4,  6,  -8;

  1, -5, 10,  -9, 16;

  1, -6, 15, -20,  9, -32;

  1, -7, 21, -35, 36,   0, 64;

  ...

CROSSREFS

Cf. A126713.

Sequence in context: A085643 A174829 A132110 * A163311 A210555 A008949

Adjacent sequences:  A039909 A039910 A039911 * A039913 A039914 A039915

KEYWORD

tabl,sign

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Vladeta Jovovic, Feb 26 2008

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 January 15 18:14 EST 2019. Contains 319153 sequences. (Running on oeis4.)