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.

A317661 Continued fraction for quaternary expansion of Liouville's number interpreted in base 4 (A012245).

Original entry on oeis.org

0, 3, 5, 15, 1, 4, 3, 16777215, 1, 2, 4, 1, 15, 5, 3, 22300745198530623141535718272648361505980415, 1, 2, 5, 15, 1, 4, 2, 1, 16777215, 3, 4, 1, 15, 5, 3
Offset: 0

Views

Author

A.H.M. Smeets, Aug 03 2018

Keywords

Crossrefs

Cf. A058304 (in base 10), A317413 (in base 2), A317414 (in base 3).

Programs

  • Maple
    with(numtheory): cfrac(add(1/4^factorial(n),n=1..7),30,'quotients'); # Muniru A Asiru, Aug 12 2018
  • Python
    n, f, i, p, q, base = 1, 1, 0, 0, 1, 4
    while i < 100000:
        i, p, q = i+1, p*base, q*base
        if i == f:
            p, n = p+1, n+1
            f = f*n
    n, a, j = 0, 0, 0
    while p%q > 0:
        a, f, p, q = a+1, p//q, q, p%q
        print(a-1, f)

Formula

In general for any Liouville's number base > 2:
a(n) = 1 if (and only if, for base > 3) n in A317331,
a(n) = base-2 if (and only if, for base > 3) n in A317332,
a(n) = base-1 if and only if n in A317333,
a(n) = base if and only if n in {8*m - 6 + 3*(m mod 2) | m > 0},
a(n) = base+1 if and only if n in {8*m - 3 - 3*(m mod 2) | m > 0},
a(n) = base^((m-1)*m!)-1 iff n in {2^m*(1+k*4) - 1 | k >= 0} union {2^m*(3+k*4) | k >= 0} for m > 1.