A366057 - OEIS

%I #10 Sep 27 2023 10:06:18

%S 1,-1,1,-1,1,0,-5,20,-55,125,-246,406,-461,-144,3004,-11978,35113,

%T -86293,181663,-314603,365922,150023,-2696308,10969573,-32970453,

%U 82976409,-178372934,314133884,-367436684,-179661091,2923282216,-11972239216,36369188841,-92517132841

%N Expansion of (1/x) * Series_Reversion( x/(1-x+x^5) ).

%F a(n) = (1/(n+1)) * Sum_{k=0..floor(n/5)} (-1)^(n-k) * binomial(n+1,k) * binomial(n-k+1,n-5*k).

%o (PARI) a(n) = sum(k=0, n\5, (-1)^(n-k)*binomial(n+1, k)*binomial(n-k+1, n-5*k))/(n+1);

%Y Cf. A364522, A365702, A366051.

%K sign

%O 0,7

%A _Seiichi Manyama_, Sep 27 2023