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.

A279239 Denominators of coefficients in expansion of (cos x)/(1 + cos(sqrt(x))).

Original entry on oeis.org

2, 8, 48, 5760, 80640, 14515200, 958003200, 1394852659200, 41845579776000, 522642751488000, 442345819668480000, 8992005822220861440000, 1240896803466478878720000, 1613165844506422542336000000, 609776689223427721003008000000
Offset: 0

Views

Author

Clark Kimberling, Dec 08 2016

Keywords

Examples

			(1/2) + (1/8)x - (11/48)x^2 - (343/5760)x^3 + ... ; 1/2, 1/3, -11/48, 1/6480, -343/5760, ... = A279238/A279239.
		

Crossrefs

Programs

  • Mathematica
    z = 26; t = CoefficientList[Series[Cos[x]/(1 + Cos[Sqrt[x]]), {x, 0, z}], x];
    Numerator[t]  (* A279238 *)
    Denominator[t]  (* A279239 *)
    %/2 (* A279240 *)

A279240 Denominators of coefficients in expansion of (2 cos x)/(1 + cos(sqrt(x))).

Original entry on oeis.org

1, 4, 24, 2880, 40320, 7257600, 479001600, 697426329600, 20922789888000, 261321375744000, 221172909834240000, 4496002911110430720000, 620448401733239439360000, 806582922253211271168000000, 304888344611713860501504000000, 4244045756995056938180935680000000
Offset: 0

Views

Author

Clark Kimberling, Dec 08 2016

Keywords

Examples

			(1/1) + (1/4)x - (11/24)x^2 - (343/2880)x^3 + (871/40320)x^4 + ... ; 1/1, 1/4, -11/24, -343/2880, ... = A279238/A279240.
		

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[2 Cos[x]/(1+Cos[Sqrt[x]]),{x,0,20}],x]//Denominator (* Harvey P. Dale, Jun 05 2024 *)

Extensions

Prior Mathematica program corrected by Harvey P. Dale, Jun 05 2024
Showing 1-2 of 2 results.