OFFSET
0,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 0..10
MATHEMATICA
a000058[0] = 2; a000058[n_Integer?NonNegative] := a000058[n] = a000058[n - 1]^2 - a000058[n - 1] + 1; a[n_Integer?NonNegative] := a[n] = DivisorSigma[1, a000058[n]]; Table[a[n], {n, 0, 9}] (* Robert P. P. McKone, Nov 05 2023 *)
PROG
(Python)
from sympy import divisor_sigma
memo = {0: 2}
def a000058(n):
if n not in memo:
memo[n] = a000058(n - 1)**2 - a000058(n - 1) + 1
return memo[n]
a = lambda n: divisor_sigma(a000058(n))
print([a(n) for n in range(10)])
# Robert P. P. McKone, Nov 05 2023
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
Sean A. Irvine, Nov 05 2023
STATUS
approved