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.

Showing 1-7 of 7 results.

A117538 Locations of the increasing peak values of the integral of the absolute value of the Riemann zeta function between successive zeros on the critical line. This can also be defined in terms of the Z function; if t and s are successive zeros of a renormalized Z function, z(x) = Z(2 Pi x/log(2)), then take the integral between t and s of |z(x)|. For each successively higher value of this integral, the corresponding term of the integer sequence is r = (t+s)/2 rounded to the nearest integer.

Original entry on oeis.org

2, 5, 7, 12, 19, 31, 41, 53, 72, 130, 171, 224, 270, 764, 954, 1178, 1395, 1578, 2684, 3395, 7033, 8269, 8539, 14348, 16808, 36269, 58973
Offset: 0

Views

Author

Gene Ward Smith, Mar 27 2006

Keywords

Comments

The fractional parts of the numbers r = (t+s)/2 above are very unevenly distributed. For all of the values in the table, the integers are in fact the unique integers contained in the interval of zeros [t, s] of z(x). An interesting challenge to anyone wishing to do computations related to the zeta function would be to find the first counterexample, where in fact the peak value interval did not contain the corresponding integer. Perhaps even more than the peak values of the zeta function themselves, these integrals are extremely closely related to relatively good equal divisions of the octave in music theory.

References

  • Edwards, H. M., Riemann's Zeta-Function, Academic Press, 1974
  • Titchmarsh, E. C., The Theory of the Riemann Zeta-Function, second revised (Heath-Brown) edition, Oxford University Press, 1986
  • Paris, R. B. and Kaminski, D., Asymptotics and Mellin-Barnes Integrals, Cambridge University Press, 2001

Crossrefs

Extensions

Extended by T. D. Noe, Apr 21 2010

A117559 Equal divisions of the octave of decreasing fifteen-limit Pepper ambiguity.

Original entry on oeis.org

1, 2, 7, 8, 24, 58, 111, 130, 224, 270, 494, 2190, 2684, 5585, 6079, 14618, 20203, 81860, 96478
Offset: 0

Views

Author

Gene Ward Smith, Mar 28 2006

Keywords

Comments

We may define the n-limit Pepper ambiguity, for any odd number n greater than one, as the maximum of the ratios of the errors of the nearest approximation to the members of the n-limit tonality diamond to the next nearest.

Crossrefs

A117555 Equal divisions of the octave of decreasing seven-limit Pepper ambiguity.

Original entry on oeis.org

1, 2, 3, 4, 12, 22, 27, 31, 99, 171, 3125, 6691, 11664, 18355, 84814, 103169
Offset: 0

Views

Author

Gene Ward Smith, Mar 28 2006

Keywords

Comments

We may define the n-limit Pepper ambiguity, for any odd number greater than one n, as the maximum of the ratios of the errors of the nearest approximation to the members of the n-limit tonality diamond to the next nearest. In the 7-limit, that means we look at the ratios of the errors for the nearest approximations to 3/2, 5/4, 5/3, 7/4, 7/5 and 7/6 to the next nearest.

Crossrefs

A117556 Equal divisions of the octave of decreasing nine-limit Pepper ambiguity.

Original entry on oeis.org

1, 2, 4, 5, 12, 19, 31, 41, 99, 171, 3125, 11664, 18355, 84814, 103169
Offset: 0

Views

Author

Gene Ward Smith, Mar 28 2006

Keywords

Comments

We may define the n-limit Pepper ambiguity, for any odd number n greater than one, as the maximum of the ratios of the errors of the nearest approximation to the members of the n-limit tonality diamond to the next nearest. In the 9-limit, that means we look at the ratios of the errors for the nearest approximations to 3/2, 5/4, 5/3, 7/4, 7/5, 7/6, 9/8, 9/7 and 9/5 to the next nearest.

Crossrefs

A117537 Locations of the midpoints of consecutive zeros of the Riemann zeta function on the critical line with increasingly large normalized spacing.

Original entry on oeis.org

2, 3, 5, 7, 12, 19, 31, 46, 53, 72, 270, 311, 954, 1178, 1308, 1395, 1578, 3395, 4190
Offset: 0

Views

Author

Gene Ward Smith, Mar 27 2006

Keywords

Comments

Equivalently, locations of consecutive real zeros of the Z function. If t and s are consecutive zeros of the Z function, we define their normalized spacing as (s-t)*log((s+t)/(4*Pi)). The sequence above is found by taking r = log(2)(s+t)/(4*Pi) and rounding to the nearest integer. These values r have a marked tendency to be close to integer values and all of the terms of the above sequence are actually contained in the intervals [s, t]*log(2)/(2*Pi).
So far as the first 100000 zeros take us, the integers of the above sequence actually fall inside the normalized intervals of zeros of Z; that is, they fall between two zeros of Z(2*Pi*t/log(2)). It would be a worthwhile project to push this computation far enough to find a counterexample. The integers above, while slightly less clearly linked to music than A117536 and A117538, are nevertheless very clearly closely related to equal divisions of the octave. Large gaps between consecutive zeros, in other words, seem to correspond to good scale divisions, though less exactly than peak values or high integrals do.

References

  • Edwards, H. M., Riemann's Zeta-Function, Academic Press, 1974
  • A. Ivic (1985). The Riemann Zeta Function, John Wiley & Sons. ISBN 0-471-80634-X.
  • Titchmarsh, E. C., The Theory of the Riemann Zeta-Function, second revised (Heath-Brown) edition, Oxford University Press, 1986

Crossrefs

A117539 Integrals of the absolute value of the Z function between successive zeros greater than or equal to the integral corresponding to 12. If we define the normalized Z function by z(x) = Z(2*Pi*x/log(2)), then the 33rd and 34th zeros are approximately 11.82 and 12.25. Integrating |z(x)| between these values gives a quantity I and the above sequence is defined as the midpoints of all successive zeros of z(x) such that the integral of |z(x)| is greater than or equal to I.

Original entry on oeis.org

12, 19, 31, 41, 46, 53, 58, 65, 72, 77, 87, 94, 99, 103, 111
Offset: 0

Views

Author

Gene Ward Smith, Mar 27 2006

Keywords

Comments

The reason for the choice of 12 as a starting point is from musical practice; 12 is the standard equal division of the octave of Western music. The subsequent values where this integral is greater than it is for 12 are also equal divisions. While all the values tabulated are such that the integer of the integer sequence is actually contained in the interval between two successive zeros, it must eventually happen that a counterexample would be found. Another interesting question is the density of this sequence; it is not clear if it is increasing in density or not.

References

  • Edwards, H. M., Riemann's Zeta-Function, Academic Press, 1974
  • Titchmarsh, E. C., The Theory of the Riemann Zeta-Function, second revised (Heath-Brown) edition, Oxford University Press, 1986

Crossrefs

A117558 Equal divisions of the octave of decreasing thirteen-limit Pepper ambiguity.

Original entry on oeis.org

1, 2, 7, 8, 24, 37, 46, 58, 130, 198, 224, 270, 494, 1506, 2684, 5585, 6079, 14618, 20203, 81860, 87939, 96478
Offset: 0

Views

Author

Gene Ward Smith, Mar 28 2006

Keywords

Comments

We may define the n-limit Pepper ambiguity, for any odd number n greater than one, as the maximum of the ratios of the errors of the nearest approximation to the members of the n-limit tonality diamond to the next nearest.

Crossrefs

Showing 1-7 of 7 results.