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 1-3 of 3 results.

A306254 Denominators of the rational factor of Kaplan's series for the Dottie number.

Original entry on oeis.org

4, 768, 61440, 165150720, 47563407360, 669692775628800, 417888291992371200, 2808209322188734464000, 3055331742541343096832000, 33437550590372458851729408000, 56175084991825730870905405440000, 7276695809501137874093602599075840000, 17464069942802730897824646237782016000000
Offset: 0

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Author

Amiram Eldar, Feb 01 2019

Keywords

Comments

These are the denominators of the unique sequence of rational numbers r_n such that d = Sum_{n>=0} r_n*Pi^(2*n+1) (where d is the Dottie number A003957). The numerators are in A302977.

Examples

			The Kaplan series begins with d = Pi/4 - Pi^3/768 - Pi^5/61440 - 43*Pi^7/165150720 - ...
		

Crossrefs

Programs

  • Mathematica
    f[x_] := x - Cos[x]; g[x_] := InverseFunction[f][x]; s = {}; Do[AppendTo[s, Denominator[(-1/2)^n * 1/n! * Derivative[n][g][Pi/2]]], {n, 1, 30, 2}]; s

A362406 Denominators of the expansion of the series reversion of sin(x) + x, odd powers only.

Original entry on oeis.org

2, 96, 1920, 1290240, 92897280, 326998425600, 51011754393600, 85699747381248000, 23310331287699456000, 63777066403145711616000, 26786367889321198878720000, 867449737727777704488468480000, 520469842636666622693081088000000, 5845917272495039506088686780416000000
Offset: 0

Views

Author

Billy Bolton, Apr 18 2023

Keywords

Examples

			f^-1(x) = (1/2)*x + (1/96)*x^3 + (1/1920)*x^5 + (43/1290240)*x^7 + ...
		

Crossrefs

Cf. A362407 (numerators).

Programs

  • PARI
    a(n) = denominator(polcoef(serreverse(sin(x + O(x^(2*n))) + x), 2*n-1)) \\ Andrew Howroyd, Apr 18 2023

Formula

Conjecture: a(n) = 2*A306254(n)/(4^(n+1)).

A362407 Numerators of the expansion of the series reversion of sin(x) + x, odd powers only.

Original entry on oeis.org

1, 1, 1, 43, 223, 60623, 764783, 107351407, 2499928867, 596767688063, 22200786516383, 64470807442488761, 3504534741776035061, 3597207408242668198973, 268918457620309807441853, 185388032403184965693274807, 18241991360742724891839902347
Offset: 0

Views

Author

Billy Bolton, Apr 18 2023

Keywords

Examples

			f^-1(x) = (1/2)*x + (1/96)*x^3 + (1/1920)*x^5 + (43/1290240)*x^7 + ...
		

Crossrefs

Cf. A362406 (denominators).

Programs

  • PARI
    a(n) = numerator(polcoef(serreverse(sin(x + O(x^(2*n))) + x), 2*n-1)) \\ Andrew Howroyd, Apr 18 2023

Formula

Conjecture: a(n) = abs(A302977(n)).
Showing 1-3 of 3 results.