OFFSET
1,2
LINKS
Indranil Ghosh, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (0,17,0,-16)
FORMULA
Add 1 to every term of A077854, then take the terms with indices 4k and 4k+3.
(1/20) [3*4^n - (-4)^n + 2*(-1)^n + 6]. - Ralf Stephan, Dec 02 2004
G.f. -x*(2*x-1)*(1+2*x)^2 / ( (x-1)*(4*x-1)*(4*x+1)*(1+x) ). - R. J. Mathar, Jun 10 2013
MATHEMATICA
LinearRecurrence[{0, 17, 0, -16}, {1, 2, 13, 26}, 24] (* Indranil Ghosh, Feb 22 2017 *)
PROG
(Python) def A091052(n): return (3*4**n-(-4)**n+2*(-1)**n+6)/20 # Indranil Ghosh, Feb 22 2017
(PARI) a(n)=(3*4^n - (-4)^n + 2*(-1)^n + 6)/20 \\ Charles R Greathouse IV, Feb 22 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Feb 23 2004
EXTENSIONS
More terms from David Wasserman, Feb 23 2006
STATUS
approved