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A091052 Record values in A091023. 3
1, 2, 13, 26, 205, 410, 3277, 6554, 52429, 104858, 838861, 1677722, 13421773, 26843546, 214748365, 429496730, 3435973837, 6871947674, 54975581389, 109951162778, 879609302221, 1759218604442, 14073748835533, 28147497671066 (list; graph; refs; listen; history; text; internal format)
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

Cf. A091023, A091053.

Sequence in context: A117983 A274869 A018400 * A294555 A031090 A294556

Adjacent sequences: A091049 A091050 A091051 * A091053 A091054 A091055

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Feb 23 2004

EXTENSIONS

More terms from David Wasserman, Feb 23 2006

STATUS

approved

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Last modified December 1 07:34 EST 2022. Contains 358454 sequences. (Running on oeis4.)