A211932 - OEIS

(Translated by https://www.hiragana.jp/)
A211932 - OEIS

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

A211932

a(n) = Sum_{ m=1..n and gcd(n,m)>1 } tau(m), where tau is the number of divisors function, A000005.

2

0, 2, 2, 5, 2, 11, 2, 13, 9, 19, 2, 28, 2, 29, 25, 32, 2, 47, 2, 50, 35, 50, 2, 69, 19, 62, 41, 72, 2, 96, 2, 80, 59, 86, 47, 114, 2, 99, 72, 118, 2, 144, 2, 125, 107, 125, 2, 164, 31, 158, 100, 151, 2, 188, 71, 174, 112, 167, 2, 229, 2, 183, 151, 188, 87, 247, 2, 208, 142, 252, 2, 271, 2, 228, 203, 238, 85

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..20000

FORMULA

a(n) = A006218(n) - A143615(n).

MAPLE

A211932 := proc(n)

local a, m;

a := 0 ;

for m from 1 to n do

if gcd(m, n) > 1 then

a := a+numtheory[tau](m) ;

end if;

end do:

a ;

end proc: # R. J. Mathar, Aug 08 2012

PROG

(PARI) A211932(n) = sum(m=1, n, if(1==gcd(n, m), 0, numdiv(m))); \\ Antti Karttunen, Jan 22 2025

CROSSREFS

Cf. A000005, A143615.

Sequence in context: A289078 A051612 A083456 * A213642 A344753 A353860

Adjacent sequences: A211929 A211930 A211931 * A211933 A211934 A211935

KEYWORD

nonn,easy

AUTHOR

Naohiro Nomoto, Aug 05 2012

STATUS

approved