A072548 - OEIS

A072548

a(n) = sigma(n) mod PrimePi(n).

0, 0, 1, 0, 0, 0, 3, 1, 2, 2, 3, 2, 0, 0, 1, 4, 4, 4, 2, 0, 4, 6, 6, 4, 6, 4, 2, 0, 2, 10, 8, 4, 10, 4, 3, 2, 0, 8, 6, 3, 5, 2, 0, 8, 2, 3, 4, 12, 3, 12, 8, 6, 8, 8, 8, 0, 10, 9, 15, 8, 6, 14, 1, 12, 0, 11, 12, 1, 11, 12, 15, 11, 9, 19, 14, 12, 0, 14, 10, 11, 16, 15, 17, 16, 17, 5, 19, 18, 18

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

OFFSET

2,7

LINKS

Michael De Vlieger, Table of n, a(n) for n = 2..10000

FORMULA

a(n) = A000203(n) mod A000720(n).

MAPLE

with(numtheory): seq(modp(sigma(n), pi(n)), n=2..100); # Muniru A Asiru, Dec 10 2018

MATHEMATICA

Table[Mod[DivisorSigma[1, w], PrimePi[w]], {w, 1, 128}]

PROG