A341330 a(n) = Sum_{k=1..n} (-k)^(k+1).

1, -7, 74, -950, 14675, -265261, 5499540, -128718188, 3358066213, -96641933787, 3041786442934, -103951418936138, 3833424966763151, -151734670591049073, 6416673685121841552, -288731231494230984304, 13774353220573494006705, -694460992134764182350927

Offset: 1

Author

John H. Chakkour, Feb 09 2021

Keywords

• sign

Crossrefs

Cf. A007778, A062815.

Programs

Mathematica

Accumulate[(-#)^(#+1)&/@Range[17]]

PARI

a(n) = sum(i=1, n, (-i)^(i+1));

Python

sum = 0
for i in range(1,20):
    sum += (-i)**(i+1)
    print(sum, end = ", ")