OFFSET
1,13
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = A000594(n) mod n.
EXAMPLE
tau(10) mod 10 = (-115920) mod 10 = 0,
tau(11) mod 11 = 534612 mod 11 = 1.
PROG
(PARI) a(n)=ramanujantau(n)%n \\ assumes the GRH; Charles R Greathouse IV, May 27 2016
(Python)
from sympy import divisor_sigma
def A273650(n): return -840*(pow(m:=n+1>>1, 2, n)*(0 if n&1 else pow(m*divisor_sigma(m), 2, n))+(sum(pow(i, 4, n)*divisor_sigma(i)*divisor_sigma(n-i) for i in range(1, m))<<1)) % n # Chai Wah Wu, Nov 08 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 27 2016
STATUS
approved