%I #8 Nov 12 2017 10:35:46
%S 1,-12,8848,-45051072,840261660928,-41695924253002752,
%T 4537436258866404364288,-951427888272965045905047552,
%U 350377450379688317757442429616128,-211362906255307072670284412178232246272,197818950974274356812042952303539935429787648
%N sech(sinh(x)*sin(x)) = 1-12/4!*x^4+8848/8!*x^8-45051072/12!*x^12...
%t With[{nn=40},Take[CoefficientList[Series[Sech[Sinh[x]Sin[x]],{x,0,nn}],x] Range[0,nn]!,{1,-1,4}]] (* _Harvey P. Dale_, Nov 12 2017 *)
%K sign
%O 0,2
%A Patrick Demichel (patrick.demichel(AT)hp.com)
%E More terms from _Harvey P. Dale_, Nov 12 2017