A013197 - OEIS

%I #7 Aug 01 2018 21:01:47

%S 0,1,0,0,4,-20,120,-560,2784,-7920,-24960,1034880,-14625536,172569280,

%T -1661936640,12339608320,-13269651456,-1902800305920,53452617646080,

%U -1037015219466240,16547577836929024,-208832669083243520

%N Expansion of e.g.f. log(sec(x) + sinh(x)).

%e x + 4/4!*x^4 - 20/5!*x^5 + 120/6!*x^6 - 560/7!*x^7 ...

%K sign

%O 0,5

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

%E a(0)=0 inserted and title improved by _Sean A. Irvine_, Aug 01 2018