A138380 First differences of A138377.
1, 2, -1, -2, -4, -8, 4, 8, 16, 32, -16, -32, -64, -128, 64, 128, 256, 512, -256, -512, -1024, -2048, 1024, 2048, 4096, 8192, -4096, -8192, -16384, -32768, 16384, 32768, 65536, 131072, -65536, -131072, -262144, -524288, 262144, 524288, 1048576, 2097152
Offset: 0
Links
- Colin Barker, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (0,0,0,-4).
Crossrefs
Cf. A138377.
Programs
-
Mathematica
Differences[LinearRecurrence[{0,0,0,-4},{0,1,3,2},60]] (* Harvey P. Dale, Mar 19 2012 *) LinearRecurrence[{0, 0, 0, -4},{1, 2, -1, -2},59] (* Ray Chandler, Aug 03 2015 *) -
PARI
Vec((1-x)*(1+x)*(1+2*x)/((1-2*x+2*x^2)*(1+2*x+2*x^2)) + O(x^100)) \\ Colin Barker, Dec 01 2015
Formula
From Colin Barker, Dec 01 2015: (Start)
a(n) = -4*a(n-4) for n>3.
G.f.: (1-x)*(1+x)*(1+2*x) / ((1-2*x+2*x^2)*(1+2*x+2*x^2)).
(End)
Extensions
More terms from Harvey P. Dale, Mar 19 2012
Missing terms added by Colin Barker, Dec 01 2015
Comments