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 1-2 of 2 results.

A288968 Exponents a(1), a(2), ... such that E_2, 1 - 24*q - 72*q^2 - ... (A006352) is equal to (1-q)^a(1) (1-q^2)^a(2) (1-q^3)^a(3) ... .

Original entry on oeis.org

24, 348, 6424, 129300, 2778648, 62114524, 1428337176, 33527349924, 799482197272, 19302454317660, 470740035601176, 11575875047000596, 286650683468840472, 7140515309818664028, 178783562850377621272, 4496350112540599930692
Offset: 1

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Author

Seiichi Manyama, Jun 20 2017

Keywords

Crossrefs

Cf. this sequence (k=2), A110163 (k=4), A288851 (k=6), A288471 (k=8), A289024 (k=10), A288990/A288989 (k=12), A289029 (k=14).
Cf. A006352 (E_2), A008683, A288877 (E_4/E_2), A289635.

Formula

a(n) = 2 + (1/(12*n)) * Sum_{d|n} A008683(n/d) * A288877(d).
a(n) = (1/n) * Sum_{d|n} A008683(n/d) * A289635(d).
a(n) ~ 1 / (n * r^(2*n)), where r = A057823. - Vaclav Kotesovec, Mar 08 2018

A211342 Decimal expansion of q between 0 and 1 maximizing Dedekind eta function eta(q) = q^(1/24) * Product_{n>=1} (1 - q^n).

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Feb 05 2013

Keywords

Examples

			0.0372768102964516581509807856516446180362823794827830067...
		

Crossrefs

Programs

  • Mathematica
    q /. Last @ FindMaximum[ DedekindEta[ -I*Log[q]/(2*Pi)], {q, 1/25}, WorkingPrecision -> 200] // RealDigits[#][[1]][[1 ;; 100]]& // Prepend[#, 0]&
    x /. FindRoot[24*Sum[DivisorSigma[1, k]*x^k, {k, 1, 1000}] == 1, {x, 1}, WorkingPrecision -> 101] (* Vaclav Kotesovec, Jun 28 2017 *)

Formula

Root of the equation Sum_{k>=1} A000203(k) * r^k = 1/24. - Vaclav Kotesovec, Jun 28 2017
Equals A057823^2. - Vaclav Kotesovec, Jul 02 2017
Showing 1-2 of 2 results.