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!)
A345724 For 1<=x<=n, 1<=y<=n, write gcd(x,y) = u*x+v*y with u,v minimal; a(n) = n^4*s, where s is the population variance of the values of u+v. 1
0, 0, 14, 48, 250, 452, 1578, 2816, 6120, 9556, 20220, 28476, 54596, 75092, 111050, 155120, 253852, 323792, 497054, 624700, 828476, 1049584, 1510824, 1792476, 2397166, 2924432, 3736358, 4469884, 5919800, 6804500, 8811122, 10401536, 12541844, 14621072, 17574850 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

The factor n^4 is to ensure that a(n) is an integer.

A345428(n) = n^2*mu where mu is the mean of the values of u+v.

The population standard deviation sqrt(s) appears to grow linearly with n.

LINKS

Table of n, a(n) for n=1..35.

PROG

(Python)

from statistics import pvariance

from sympy.core.numbers import igcdex

def A345724(n): return pvariance(n**2*(u+v) for u, v, w in (igcdex(x, y) for x in range(1, n+1) for y in range(1, n+1)))

CROSSREFS

Cf. A345428, A345687, A345688, A345689, A345690, A345691.

Sequence in context: A205468 A195966 A337421 * A121202 A345691 A251228

Adjacent sequences:  A345721 A345722 A345723 * A345725 A345726 A345727

KEYWORD

nonn

AUTHOR

Chai Wah Wu, Jun 24 2021

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 18 09:26 EST 2022. Contains 350454 sequences. (Running on oeis4.)