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.

Previous Showing 11-17 of 17 results.

A329337 Continued fraction of A328907 = 0.6009668516..., solution to 1 + 3^x = 6^x.

Original entry on oeis.org

0, 1, 1, 1, 1, 40, 1, 3, 2, 1, 2, 23, 1, 13, 1, 8, 1, 15, 2, 3, 103, 4, 10, 4, 2, 2, 2, 1, 1, 84, 1, 4, 1, 3, 1, 1, 5, 1, 7, 23, 8, 1, 8, 24, 1, 1, 2, 12, 39, 14, 19, 3, 4, 8, 3, 2, 1, 4, 1, 8, 1, 1, 1, 2, 1, 10, 1, 35, 1, 10, 2, 2, 2, 1, 1, 15, 2, 3, 1, 4, 7, 5, 1, 9, 1, 1, 1, 1, 2, 3, 3, 2, 1, 4, 54, 4, 1, 3, 2, 1, 1, 1, 1, 4, 22, 1, 4, 3, 1, 1, 1, 2, 6, 1, 1, 4, 1, 8, 1, 20
Offset: 0

Views

Author

M. F. Hasler, Nov 11 2019

Keywords

Examples

			0.6009668516... = 0 + 1/(1 + 1/(1 + 1/(1 + 1/(1 + 1/(40 + 1/(1 + 1/(3 + ...)))))))
		

Crossrefs

Cf. A328912 (cont. frac. of A242208: 1 + 2^x = 4^x), A328913 (cont. frac. of A328900: 2^x + 3^x = 4^x), A329335 (cont. frac. of A328905: 1 + 2^x = 5^x).

Programs

  • Mathematica
    ContinuedFraction[x/.FindRoot[1+3^x==6^x,{x,1},WorkingPrecision->150]] (* Harvey P. Dale, Jun 13 2022 *)
  • PARI
    contfrac(c=solve(x=0,1, 1+3^x-6^x))[^-1] \\ discarding possibly incorrect last term. Use e.g. \p999 to get more terms. - M. F. Hasler, Oct 31 2019

A242047 Decimal expansion of the asymptotic growth rate of the number of odd coefficients in Pascal "sextinomial" triangle mod 2, where coefficients are from (1+x+x^2+x^3+x^4+x^5)^n.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Aug 13 2014

Keywords

Examples

			0.819469462165540146595937684377285598615124623543141209347...
		

Crossrefs

Cf. A242208 (1+x+x^2)^n, A242021 (1+x+x^3)^n, A242022 (1+x+x^2+x^3+x^4)^n, A241002 (1+x+x^4)^n.

Programs

  • Mathematica
    mu = Sort[Table[Root[x^6 - 4*x^5 + x^4 - x^3 + 8*x^2 + 11*x + 8, x, n], {n, 1, 5}], N[Abs[#1]] < N[Abs[#2]] &] // Last; RealDigits[Log[mu]/Log[2] - 1, 10, 104] // First

Formula

log(abs(mu))/log(2) - 1, where mu is the root of x^6 - 4*x^5 + x^4 - x^3 + 8*x^2 + 11*x + 8 with maximum modulus.

A242049 Decimal expansion of 'lambda', the Lyapunov exponent characterizing the asymptotic growth rate of the number of odd coefficients in Pascal trinomial triangle mod 2, where coefficients are from (1+x+x^2)^n.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Aug 13 2014

Keywords

Examples

			0.429947433342452720114697035519922323324065011589304617040276...
= log(1.53717671718235794959014032895522160250150809343236...)
		

Crossrefs

Cf. A338294.
Cf. A242208 (1+x+x^2)^n, A242021 (1+x+x^3)^n, A242022 (1+x+x^2+x^3+x^4)^n, A241002 (1+x+x^4)^n, A242047 (1+x+...+x^4+x^5)^n, A242048 (1+x+...+x^5+x^6)^n.

Programs

  • Mathematica
    digits = 105; lambda = (1/4)*NSum[Log[(1/3)*(2^(k+2) - (-1)^k)]/2^k, {k, 1, Infinity}, WorkingPrecision -> digits + 5, NSumTerms -> 500]; RealDigits[lambda, 10, digits] // First
  • PARI
    (1/4)*suminf(k=1, (log((1/3)*(2^(k+2) - (-1)^k))/2^k)) \\ Michel Marcus, May 14 2020

Formula

Equals (1/4)*Sum_{k >= 1} (log((1/3)*(2^(k+2) - (-1)^k))/2^k).
From Kevin Ryde, Feb 13 2021: (Start)
Equals log(A338294).
Equals Sum_{k>=1} (1/k)*( 1/(1+(-2)^(k+1)) - 1/(-3)^k ) (an alternating series).
(End)

A329336 Continued fraction of A328906 = 0.4895363211996..., solution to 1 + 2^x = 6^x.

Original entry on oeis.org

0, 2, 23, 2, 1, 1, 4, 1, 1, 27, 4, 12, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 2, 1, 2, 1, 2, 6, 1, 10, 4, 3, 4, 1, 2, 1, 1, 43, 69, 1, 2, 41, 1, 3, 2, 3, 3, 1, 5, 4, 1, 1, 1, 7, 1, 1, 1, 11, 13, 2, 3, 1, 1, 1, 118, 2, 1, 1, 12, 1, 2, 2, 2, 6, 2, 3, 1, 4, 1, 8, 1, 1, 18, 2, 21, 1, 4, 1, 3, 1, 51, 6, 1, 1, 18, 2, 1, 1, 2, 56, 1, 1, 5, 4, 1, 4, 7, 1, 2, 2, 1, 9, 76, 2, 1, 3, 1, 5, 3, 1, 7, 6
Offset: 0

Views

Author

M. F. Hasler, Nov 11 2019

Keywords

Examples

			0.4895363211996... = 0 + 1/(2 + 1/(23 + 1/(2 + 1/(1 + 1/(1 + 1/(4 + 1/...))))))
		

Crossrefs

Cf. A328912 (cont. frac. of A242208: 1 + 2^x = 4^x), A328913 (cont. frac. of A328900: 2^x + 3^x = 4^x), A329334 (cont. frac. of A328904: 1 + 3^x = 5^x).

Programs

  • Mathematica
    ContinuedFraction[x/.FindRoot[1+2^x==6^x,{x,.4},WorkingPrecision->1000],150] (* Harvey P. Dale, Oct 15 2022 *)
  • PARI
    contfrac(c=solve(x=0,1, 1+2^x-6^x))[^-1] \\ discarding possibly incorrect last term. Use e.g. \p999 to get more terms. - M. F. Hasler, Oct 31 2019

A242048 Decimal expansion of the asymptotic growth rate of the number of odd coefficients in Pascal "septinomial" triangle mod 2, where coefficients are from (1+x+...+x^5+x^6)^n.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Aug 13 2014

Keywords

Examples

			0.83179639673444068999389310745866895732592855850213772205535...
		

Crossrefs

Cf. A242208 (1+x+x^2)^n, A242021 (1+x+x^3)^n, A242022 (1+x+x^2+x^3+x^4)^n, A241002 (1+x+x^4)^n, A242047 (1+x+...+x^4+x^5)^n.

Programs

  • Mathematica
    mu = Sort[Table[Root[x^6 - x^5 - 2*x^4 - 28*x^3 + 16*x + 64, x, n], {n, 1, 5}], N[Abs[#1]] < N[Abs[#2]]&] // Last; RealDigits[Log[mu]/Log[2] - 1, 10, 102] // First

Formula

log(abs(mu))/log(2) - 1, where mu is the root of x^6 - x^5 - 2*x^4 - 28*x^3 + 16*x + 64 with maximum modulus.

A318057 a(n) is the number of binary places to which n-th convergent of continued fraction expansion of the golden section matches the correct value.

Original entry on oeis.org

0, -2, 3, 2, 5, 2, 6, 9, 10, 9, 13, 12, 15, 16, 19, 16, 20, 22, 24, 25, 27, 29, 28, 30, 33, 32, 36, 32, 38, 32, 41, 42, 44, 45, 46, 47, 50, 48, 52, 54, 53, 56, 53, 58, 59, 60, 64, 62, 66, 62, 67, 69, 71, 73, 75, 74, 77, 78, 80, 82, 81, 84, 81, 87, 81, 88, 90
Offset: 1

Views

Author

A.H.M. Smeets, Aug 14 2018

Keywords

Comments

The correct binary value of the golden section is given in A068432; the continued fraction terms of the golden section is given in A000012.
For the number of correct decimal digits of the golden section see A318058.
The denominator of the k-th convergent obtained from a continued fraction tend to k*A001622; the error between the k-th convergent and the constant itself tends to 1/(2*k*A001622), or in binary digits 2*k*log(A001622)/log(2) bits after the binary point.
The sequence for quaternary digits is obtained by floor(a(n)/2), the sequence for octal digits is obtained by floor(a(n)/3), and the sequence for hexadecimal digits is obtained by floor(a(n)/4).

Examples

			   n   convergent         binary expansion       a(n)
  ==  =============  ==========================  ====
   1    1 / 1          1.0                         0
   2    2 / 1         10.0                        -2
   3    3 / 2          1.1000                      3
   4    5 / 3          1.101                       2
   5    8 / 5          1.100110                    5
   6   13 / 8          1.101                       2
   7   21 / 13         1.1001110                   6
   8   34 / 21         1.1001111001                9
   9   55 / 34         1.10011110000              10
  10   89 / 55         1.1001111001                9
  oo  lim = A068432    1.1001111000110111011110   --
		

Crossrefs

Programs

  • Python
    p, q, i, base = 1, 1, 0, 2
    while i < 20200:
        p, q, i = p+q, p, i+1
    a0, p, q = p//q, q, p
    i, p, dd = 0, p*base, [0]
    while i < 30000:
        d, p, i = p//q, (p%q)*base, i+1
        dd = dd+[d]
    n, pn, qn = 0, 1, 0
    while n < 20000:
        n, pn, qn = n+1, pn+qn, pn
        if pn//qn != a0:
            print(n, "- manual!")
        else:
            i, p, q, di = 0, (pn%qn)*base, qn, 0
            while di == dd[i]:
                i, di, p = i+1, p//q, (p%q)*base
            print(n, i-1)

Formula

Lim {n -> oo} a(n)/n = 2*log(A001622)/log(2) = 2*A002390/log(2) = A202543/log(2) = 2*A242208.

A329335 Continued fraction of A328905 = 0.5638955242599..., solution to 1 + 2^x = 5^x.

Original entry on oeis.org

0, 1, 1, 3, 2, 2, 2, 1, 3, 3, 1, 5, 3, 1, 1, 3, 1, 1, 6, 1, 36, 20, 18, 3, 1, 3, 2, 1, 2, 9, 3, 2, 1, 1, 1, 2, 7, 1, 1, 5, 1, 112, 2, 1, 6, 2, 1, 1, 1, 1, 2, 44, 1, 2, 3, 70, 1, 1, 1, 12, 3, 1, 5, 6, 1, 1, 10, 4, 4, 2, 3, 1, 7, 1, 4, 1, 1, 1, 5, 2, 1, 5, 1, 4, 3, 1, 1, 1, 1, 2, 1, 1, 4, 6, 7, 2
Offset: 0

Views

Author

M. F. Hasler, Nov 11 2019

Keywords

Examples

			0.5638955242599... = 0 + 1/(1 + 1/(1 + 1/(3 + 1/(2 + 1/(2  + 1/(2 + 1/...))))))
		

Crossrefs

Cf. A328912 (cont. frac. of A242208: 1 + 2^x = 4^x), A328913 (cont. frac. of A328900: 2^x + 3^x = 4^x), A329337 (cont. frac. of A328907: 1 + 3^x = 6^x).

Programs

  • PARI
    contfrac(c=solve(x=0,1, 1+2^x-5^x))[^-1] \\ discarding possibly incorrect last term. Use e.g. \p999 to get more terms. - M. F. Hasler, Oct 31 2019
Previous Showing 11-17 of 17 results.