This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A132084 #9 Sep 17 2015 02:53:26 %S A132084 1,3,30,42,30,66,2730,6,510,798,330,138,2730,6,870,14322,510,6, %T A132084 1919190,6,13530,1806,690,282,46410,66,1590,798,870,354,56786730,6, %U A132084 510,64722,30,4686,140100870,6,30,3318,230010,498,3404310,6,61410,272118,1410,6,4501770 %N A132084 A051717(2n). %C A132084 Essentially the same as A006954. %C A132084 a(2n) + a(2n+1) = 4, 72, 96, 2736, 1308, 468, ... are multiples of 4. %p A132084 C:=proc(n) if n=0 then RETURN(1); fi; if n mod 2 = 0 then RETURN(bernoulli(n)+bernoulli(n-1)); else RETURN(-bernoulli(n)-bernoulli(n-1)); fi; end; %p A132084 A051717 := proc(n) denom(C(n)) ; end: A132084 := proc(n) A051717(2*n) ; end: seq(A132084(n),n=0..120) ; # _R. J. Mathar_, Sep 07 2009 %K A132084 nonn,frac %O A132084 0,2 %A A132084 _Paul Curtz_, Aug 26 2008 %E A132084 Extended by _R. J. Mathar_, Sep 07 2009