cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A372869 Decimal expansion of the number whose continued fraction coefficients are given in A084580.

Original entry on oeis.org

5, 8, 1, 5, 8, 0, 3, 3, 5, 8, 8, 2, 8, 3, 2, 9, 8, 5, 6, 1, 4, 5, 0, 0, 6, 0, 7, 2, 2, 8, 0, 6, 5, 5, 2, 4, 7, 7, 6, 3, 0, 5, 6, 6, 9, 6, 2, 0, 0, 9, 2, 3, 0, 1, 3, 6, 2, 1, 2, 1, 5, 5, 5, 1, 5, 7, 6, 7, 1, 0, 4, 9, 1, 2, 4, 1, 9, 5, 3, 4, 0, 8, 9, 4, 9, 2, 0, 1, 2, 6, 9, 4, 1, 4, 2, 1, 2, 9, 0, 9, 2, 8, 0, 5, 9, 2, 1, 2, 8, 8, 7, 8, 6, 1, 7, 6, 8, 0, 8, 0, 4, 1, 3, 2, 1, 3, 6, 3, 7, 5, 7, 8, 3, 2, 6
Offset: 0

Views

Author

Jwalin Bhatt, Jul 04 2024

Keywords

Examples

			0.5815803358828329856145006072280655247763056696200923013621215551576710...
		

Crossrefs

Cf. A084580 (continued fraction).

Programs

  • Python
    # Using `sample_gauss_kuzmin_distribution` function from A084580.
    from mpmath import mp, iv
    def decimal_from_cf(coeffs):
        num = iv.mpf([coeffs[-1], coeffs[-1]+1])
        for coeff in coeffs[-2::-1]:
            num = coeff + 1/iv.mpf(num)
        return 1/num
    def get_matching_digits(interval_a, interval_b):
        match_index = 0
        for i, j in zip(interval_a, interval_b):
            if i != j:  break
            match_index += 1
        return interval_a[:match_index]
    def compute_kuzmin_digits(prec, num_coeffs):
        assert prec > num_coeffs
        mp.dps = iv.dps = prec
        coeffs = sample_gauss_kuzmin_distribution(num_coeffs)
        x = decimal_from_cf(coeffs)
        a = mp.nstr(mp.mpf(x.a), n=prec, strip_zeros=False)
        b = mp.nstr(mp.mpf(x.b), n=prec, strip_zeros=False)
        return get_matching_digits(a, b)
    num = compute_kuzmin_digits(prec=200, num_coeffs=180)
    A372869 = [int(d) for d in num[1:] if d != '.']