A116969 If n mod 2 = 0 then 3*2^(n-1)+n-1 else 3*2^(n-1)+n.

4, 7, 15, 27, 53, 101, 199, 391, 777, 1545, 3083, 6155, 12301, 24589, 49167, 98319, 196625, 393233, 786451, 1572883, 3145749, 6291477, 12582935, 25165847, 50331673, 100663321, 201326619, 402653211, 805306397, 1610612765, 3221225503, 6442450975, 12884901921

Offset

1,1

Comments

Number of moves to solve Easy Pagoda puzzle.

References

Richard I. Hess, Compendium of Over 7000 Wire Puzzles, privately printed, 1991.

Richard I. Hess, Analysis of Ring Puzzles, booklet distributed at 13th International Puzzle Party, Amsterdam, Aug 20 1993.

Links

Table of n, a(n) for n=1..33.

Index entries for linear recurrences with constant coefficients, signature (3,-1,-3,2).

Formula

a(n) = 3*a(n-1)-a(n-2)-3*a(n-3)+2*a(n-4). G.f.: -x*(x^3-2*x^2-5*x+4) / ((x-1)^2*(x+1)*(2*x-1)). - Colin Barker, Jul 18 2013

Maple

f:=n-> if n mod 2 = 0 then 3*2^(n-1)+n-1 else 3*2^(n-1)+n; fi;

Mathematica

f[n_]:=If[EvenQ[n], 3*2^(n-1)+n-1, 3*2^(n-1)+n]; f/@Range[40] (* Harvey P. Dale, Sep 21 2012 *)

Crossrefs

Sequence in context: A295728 A027419 A301204 * A131090 A178615 A131935

Adjacent sequences: A116966 A116967 A116968 * A116970 A116971 A116972

Keyword

nonn,easy

Author

N. J. A. Sloane, Apr 01 2006

Extensions

More terms from Colin Barker, Jul 18 2013

Status

approved