a(n) = -4*(((n+1)^(n+1)-(n+1))/((n+1)-1)^2-1)/((-3+(-1)^n)*n).
A221741
a(n) = -4*(((n+1)^(n+1)-(n+1))/((n+1)-1)^2-1)/((-3+(-1)^n)*n).
Terms
- a(0) =1a(1) =5a(2) =9a(3) =97a(4) =373a(5) =7625a(6) =48913a(7) =1513361a(8) =13717421a(9) =570623341a(10) =6698798233a(11) =350549891889
External references
- oeis: A221741