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%I #9 Feb 18 2021 16:13:32
%S 1,-7,74,-950,14675,-265261,5499540,-128718188,3358066213,
%T -96641933787,3041786442934,-103951418936138,3833424966763151,
%U -151734670591049073,6416673685121841552,-288731231494230984304,13774353220573494006705,-694460992134764182350927
%N a(n) = Sum_{k=1..n} (-k)^(k+1).
%t Accumulate[(-#)^(#+1)&/@Range[17]]
%o (PARI) a(n) = sum(i=1, n, (-i)^(i+1));
%o (Python)
%o sum = 0
%o for i in range(1,20):
%o sum += (-i)**(i+1)
%o print(sum, end = ", ")
%Y Cf. A007778, A062815.
%K sign
%O 1,2
%A _John H. Chakkour_, Feb 09 2021
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