A363031 a(n) = sigma(6*n+1). Sum of the divisors of 6*n+1, n >= 0.

1, 8, 14, 20, 31, 32, 38, 44, 57, 72, 62, 68, 74, 80, 108, 112, 98, 104, 110, 144, 133, 128, 160, 140, 180, 152, 158, 164, 183, 248, 182, 216, 194, 200, 252, 212, 256, 224, 230, 288, 242, 280, 288, 304, 324, 272, 278, 284, 307, 360, 352, 308, 314, 360, 434, 332, 338, 400, 350, 432, 381, 368, 374, 380, 576, 432

Offset: 0

Author

Omar E. Pol, May 18 2023

Keywords

• nonn
• easy

Comments

The sum of divisors function A000203 seems to behave with a certain periodicity of period 6.

Links

• Michael De Vlieger, Table of n, a(n) for n = 0..9999

Crossrefs

Partial sums give A363161.

Cf. A000203, A016921, A224613.

Programs

Mathematica

Array[DivisorSigma[1, 6 # + 1] &, 66, 0] (* Michael De Vlieger, Aug 27 2023 *)

PARI

a(n) = sigma(6*n+1); \\ Michel Marcus, Aug 28 2023

Python

from sympy import divisor_sigma
def A363031(n): return divisor_sigma(6*n+1) # Chai Wah Wu, Sep 07 2023

Formula

a(n) = A000203(6*n+1).

a(n) = A000203(A016921(n)).