A174007 a(2n+1)=2. a(2n)= 1-n.

2, 0, 2, -1, 2, -2, 2, -3, 2, -4, 2, -5, 2, -6, 2, -7, 2, -8, 2, -9, 2, -10, 2, -11, 2, -12, 2, -13, 2, -14, 2, -15, 2, -16, 2, -17, 2, -18, 2, -19, 2, -20, 2, -21, 2, -22, 2, -23, 2, -24, 2, -25, 2, -26, 2, -27, 2, -28, 2, -29, 2, -30, 2, -31, 2, -32, 2, -33, 2, -34, 2, -35, 2

Offset

1,1

Comments

A064680(n)+A022998(n-1) =c(n) = 2, 2, 10, 5, 18, 8, 26, 11,.. has differences c(2n)-c(2n-1) = -5*(n-1) = -A008587(n-1).

Links

Table of n, a(n) for n=1..73.

Index entries for linear recurrences with constant coefficients, signature (0,2,0,-1).

Formula

a(n) = n/4+3/2-(-1)^n*(n/4+1/2).

a(n)= +2*a(n-2) -a(n-4). G.f.: -x*(-2+2*x^2+x^3) / ( (x-1)^2*(1+x)^2 ).

a(n+1)-a(n) = (-1)^n*A008619(n+1).

a(n) = A064680(n)-A022998(n-1).

Crossrefs

Cf. A147657.

Sequence in context: A029345 A153149 A249072 * A330709 A045450 A347419

Adjacent sequences: A174004 A174005 A174006 * A174008 A174009 A174010

Keyword

easy,sign

Author

Paul Curtz, Mar 05 2010

Status

approved