A091052 Record values in A091023.
1, 2, 13, 26, 205, 410, 3277, 6554, 52429, 104858, 838861, 1677722, 13421773, 26843546, 214748365, 429496730, 3435973837, 6871947674, 54975581389, 109951162778, 879609302221, 1759218604442, 14073748835533, 28147497671066
Offset: 1
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)
Programs
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Mathematica
LinearRecurrence[{0,17,0,-16},{1,2,13,26},24] (* 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
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Python
def A091052(n): return (3*4**n-(-4)**n+2*(-1)**n+6)/20 # Indranil Ghosh, Feb 22 2017
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
Extensions
More terms from David Wasserman, Feb 23 2006