A273960 a(n) = (-1)^n*prime(n).

-2, 3, -5, 7, -11, 13, -17, 19, -23, 29, -31, 37, -41, 43, -47, 53, -59, 61, -67, 71, -73, 79, -83, 89, -97, 101, -103, 107, -109, 113, -127, 131, -137, 139, -149, 151, -157, 163, -167, 173, -179, 181, -191, 193, -197, 199, -211, 223, -227, 229, -233, 239, -241, 251, -257, 263, -269, 271

Offset: 1

Author

Terry D. Grant, Jun 12 2016

Keywords

• sign

Examples

			a(1) = 2*(-1)^1 = -2.
a(2) = 3*(-1)^2 = 3.
a(3) = 5*(-1)^3 = -5.
		

Crossrefs

Cf. A000040, A083236.

Programs

Mathematica

Table[Prime[n]*(-1)^n,{n,1,70}]
Table[If[OddQ[n],-Prime[n],Prime[n]],{n,70}] (* Harvey P. Dale, Jul 01 2016 *)

PARI

a(n) = prime(n)*(-1)^n \\ Felix Fröhlich, Jun 15 2016

Formula

a(n) = A000040(n)*A033999(n). - Felix Fröhlich, Jun 15 2016