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.

A349267 Generalized Euler numbers, a(n) = n!*[x^n](sec(8*x)*2*(sin(4*x) + cos(4*x))).

Original entry on oeis.org

2, 8, 96, 1408, 29184, 739328, 22634496, 806453248, 32864600064, 1506300919808, 76717014122496, 4297849713983488, 262665886073094144, 17390688314209599488, 1239981021847665770496, 94727563504456856240128, 7719096548270543600615424, 668321603392783694711226368
Offset: 0

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Author

Peter Luschny, Nov 21 2021

Keywords

Comments

For references and cross references, compare the overview in A349264.

Crossrefs

Row 8 of A349271.
Bisections: A064069, A064073.
Cf. A349264.

Programs

  • Maple
    sec(8*x)*2*(sin(4*x) + cos(4*x)): series(%, x, 20): seq(n!*coeff(%, x, n), n = 0..17);
  • Mathematica
    m = 17; CoefficientList[Series[2 * Sec[8*x] * (Sin[4*x] + Cos[4*x]), {x, 0, m}], x] * Range[0, m]! (* Amiram Eldar, Nov 21 2021 *)