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 A012989 E.g.f. cos(arctan(x)+arcsin(x)) = ((1-x^2)^(1/2) - x^2)/(1+x^2)^(1/2), even powers only. 0
 1, -4, 24, -630, 27720, -2353050, 267567300, -46909412550, 10103827734000, -3007951147451250, 1049953727680357500, -474655168783984938750, 244316469166238814345000, -155979504015802517206406250 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS EXAMPLE ((1-x^2)^(1/2) - x^2)/(1+x^2)^(1/2) = 1-4/2!*x^2+24/4!*x^4-630/6!*x^6+27720/8!*x^8... MATHEMATICA mx = 13; Delete[ Range[0, 2 mx]! CoefficientList[ Series[ (Sqrt[1 - x^2] - x^2)/Sqrt[1 + x^2], {x, 0, 2 mx}], x], Split[2 Range@ mx]] (* Robert G. Wilson v, Oct 22 2012 *) With[{nn=30}, Take[CoefficientList[Series[Cos[ArcTan[x]+ArcSin[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Dec 12 2018 *) CROSSREFS Sequence in context: A216092 A174245 A228191 * A347480 A058171 A196866 Adjacent sequences: A012986 A012987 A012988 * A012990 A012991 A012992 KEYWORD sign AUTHOR Patrick Demichel (patrick.demichel(AT)hp.com) EXTENSIONS Name corrected, and e.g.f. simplified by Sergei N. Gladkovskii and Joerg Arndt, Oct 23 2012. STATUS approved

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Last modified March 25 23:06 EDT 2023. Contains 361529 sequences. (Running on oeis4.)