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A133212 a(n) = 4a(n-1) - 6a(n-2) + 4a(n-3), n > 3; a(0) = 1, a(1) = 4, a(2) = 12, a(3) = 32. 2
1, 4, 12, 32, 72, 144, 272, 512, 992, 1984, 4032, 8192, 16512, 33024, 65792, 131072, 261632, 523264, 1047552, 2097152, 4196352, 8392704, 16781312, 33554432, 67100672, 134201344, 268419072, 536870912, 1073774592, 2147549184 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Conjecture: a(n) = 2*A038503(n+3) if n>0. - R. J. Mathar, Oct 23 2007

LINKS

Table of n, a(n) for n=0..29.

Index entries for linear recurrences with constant coefficients, signature (4, -6, 4).

FORMULA

Sequence is identical to its fourth differences.

G.f.: -(1+2*x^2)/((2*x-1)*(2*x^2-2*x+1)). a(n) = -2*(-1)^n*A009116(n)+3*2^n. - R. J. Mathar, Nov 18 2007

MAPLE

A133212 := proc(n) option remember ; if n <= 3 then op(n+1, [1, 4, 12, 32]) ; else 4*A133212(n-1)-6*A133212(n-2)+4*A133212(n-3) ; fi ; end: seq(A133212(n), n=0..50) ; # R. J. Mathar, Oct 23 2007

MATHEMATICA

Join[{1}, LinearRecurrence[{4, -6, 4}, {4, 12, 32}, 29]] (* Ray Chandler, Sep 23 2015 *)

CROSSREFS

Cf. A009116, A099087.

Sequence in context: A028922 A066150 A233458 * A233447 A127811 A138517

Adjacent sequences:  A133209 A133210 A133211 * A133213 A133214 A133215

KEYWORD

nonn,easy

AUTHOR

Paul Curtz, Oct 11 2007

EXTENSIONS

More terms from R. J. Mathar, Oct 23 2007

STATUS

approved

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Last modified April 19 01:29 EDT 2019. Contains 322237 sequences. (Running on oeis4.)