A013474 Expansion of cos(cos(x)-cosh(x)).

1, -12, 1568, -445632, 76844288, 278739068928, -467851397312512, -2679102291371999232, 13369295760767407751168, 198192229563606535497842688, -1400852802790123139561996419072, -65350779506647538962325382377766912

Offset

0,2

Links

Table of n, a(n) for n=0..11.

Example

cos(cos(x)-cosh(x))=1-12/4!*x^4+1568/8!*x^8-445632/12!*x^12...

Mathematica

With[{nn=50}, Take[CoefficientList[Series[Cos[Cos[x]-Cosh[x]], {x, 0, nn}], x] Range[0, nn-2]!, {1, -1, 4}]] (* Harvey P. Dale, May 02 2020 *)

Prog

(PARI) a(n)=if(n<0, 0, (4*n)!*polcoeff(cos(cos(x+x*O(x^(4*n)))-cosh(x+x*O(x^(4*n)))), 4*n))

Crossrefs

Sequence in context: A299694 A366832 A160237 * A013515 A159383 A015011

Adjacent sequences: A013471 A013472 A013473 * A013475 A013476 A013477

Keyword

sign,easy

Author

Patrick Demichel (patrick.demichel(AT)hp.com)

Extensions

More terms from Ralf Stephan, Jan 17 2003

Status

approved