In number theory, the gcd-sum function,[1]
also called Pillai's arithmetical function,[1] is defined for every by
or equivalently[1]
where is a divisor of and is Euler's totient function.
it also can be written as[2]
where, is the divisor function, and is the Möbius function.
This multiplicative arithmetical function was introduced by the Indian mathematician Subbayya Sivasankaranarayana Pillai in 1933.[3]
[4]
- ^ a b c Lászlo Tóth (2010). "A survey of gcd-sum functions". J. Integer Sequences. 13.
- ^ Sum of GCD(k,n)
- ^ S. S. Pillai (1933). "On an arithmetic function". Annamalai University Journal. II: 242–248.
- ^ Broughan, Kevin (2002). "The gcd-sum function". Journal of Integer Sequences. 4 (Article 01.2.2): 1–19.