A374333 a(n) is the denominator of x(n) = (2*x(n-1) + 1/n) mod 1, with x(0) = 0.

1, 1, 2, 3, 12, 30, 30, 105, 840, 1260, 63, 693, 2772, 18018, 18018, 45045, 720720, 6126120, 3063060, 29099070, 58198140, 29099070, 29099070, 334639305, 2677114440, 6692786100, 1673196525, 5019589575, 20078358300, 291136195350, 291136195350, 4512611027925, 144403552893600

Offset: 0

Author

Paolo Xausa, Jul 06 2024

Keywords

• nonn
• frac

Comments

See A374332 for details and links.

Links

• Paolo Xausa, Table of n, a(n) for n = 0..2000

Crossrefs

Cf. A374332 (numerators), A374335.

Programs

Mathematica

Block[{n = 0}, Denominator[NestList[Mod[2*# + 1/++n, 1] &, 0, 50]]]

PARI

x(n) = if (n==0, 0, 2*x(n-1) + 1/n);
a(n) = denominator(frac(x(n))); \\ Michel Marcus, Jul 13 2024

Python

from itertools import count, islice
from fractions import Fraction
def A374333_gen(): # generator of terms
    a = Fraction(0,1)
    for n in count(1):
        yield a.denominator
        a = (2*a+Fraction(1,n)) % 1
A374333_list = list(islice(A374333_gen(),20)) # Chai Wah Wu, Jul 13 2024