A137206 First differences of A074323.

0, 2, -1, 4, -2, 8, -4, 16, -8, 32, -16, 64, -32, 128, -64, 256, -128, 512, -256, 1024, -512, 2048, -1024, 4096, -2048, 8192, -4096, 16384, -8192, 32768, -16384, 65536, -32768, 131072, -65536, 262144, -131072, 524288, -262144, 1048576, -524288, 2097152, -1048576

Offset

0,2

Links

Matthew House, Table of n, a(n) for n = 0..6605

Index entries for linear recurrences with constant coefficients, signature (0,2).

Formula

From R. J. Mathar, Apr 22 2009: (Start)

G.f.: x*(2-x)/(1-2*x^2).

a(n) = (-1)^(n+1)*A135530(n-1). (End)

a(n) = 2*a(n-2). - Matthew House, Jan 15 2017

Mathematica

LinearRecurrence[{0, 2}, {0, 2, -1}, 50] (* Paolo Xausa, Jun 03 2026 *)

Prog

(PARI) a(n)=if(n, ([0, 1; 2, 0]^(n-1)*[2; -1])[1, 1], 0) \\ Charles R Greathouse IV, Jun 03 2026

Crossrefs

Cf. A000079, A131577, A135530, A074323.

Sequence in context: A265256 A135530 A076736 * A182906 A193359 A344613

Adjacent sequences: A137203 A137204 A137205 * A137207 A137208 A137209

Keyword

sign,easy

Author

Paul Curtz, Mar 05 2008

Extensions

More terms from R. J. Mathar, Apr 22 2009

Status

approved