A013474 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A013474

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

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

(list; graph; refs; listen; history; text; internal format)

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