A367131 a(n) is the sum of the divisors of A000058(n) (Sylvester's sequence).
3, 4, 8, 44, 1960, 3263444, 10697794573312, 113429214231136770625234912, 12864938683281101589385656009398714729057117020127552, 166504803622354833425112235578181474001920862856209391632362182416351065666575351284563698791731209336320
Offset: 0
Keywords
Links
- Amiram Eldar, Table of n, a(n) for n = 0..10
- Wikipedia, Sylvester's sequence: Divisibility and factorizations.
Programs
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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 *) -
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