A156591 First differences of A154570.

2, -7, 6, -8, 4, -12, -4, -28, -36, -92, -164, -348, -676, -1372, -2724, -5468, -10916, -21852, -43684, -87388, -174756, -349532, -699044, -1398108, -2796196, -5592412, -11184804, -22369628, -44739236, -89478492, -178956964, -357913948, -715827876

Offset: 0

Author

Paul Curtz, Feb 10 2009

Keywords

• sign
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (1, 2).

Programs

Mathematica

LinearRecurrence[{1,2},{2,-7,6},40] (* Harvey P. Dale, Feb 01 2025 *)

Formula

a(n)+a(n+1) = -A000079(n-1), n>0.

a(n+1) = 4*(-1)^(n+1)- A154879(n).

G.f.: (1-3*x)*(2-3*x)/((1+x)*(1-2*x)). a(n) = -2^n/6+20*(-1)^n/3, n>0. - R. J. Mathar, Feb 25 2009

Extensions

Edited by R. J. Mathar, Feb 25 2009