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A133212
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a(n) = 4a(n-1)-6a(n-2)+ 4 a(n-3), n > 3; a(0) = 1, a(1) = 4, a(2) = 12, a(3) = 32.
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2
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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
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OFFSET
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0,2
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COMMENTS
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Conjecture: a(n)=2*A038503(n+3) if n>0. - R. J. Mathar, Oct 23 2007
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LINKS
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Table of n, a(n) for n=0..29.
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FORMULA
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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
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MAPLE
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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
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CROSSREFS
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Cf. A009116, A099087.
Sequence in context: A028921 A028922 A066150 * A127811 A138517 A001934
Adjacent sequences: A133209 A133210 A133211 * A133213 A133214 A133215
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KEYWORD
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nonn,easy
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AUTHOR
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Paul Curtz, Oct 11 2007
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EXTENSIONS
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More terms from R. J. Mathar, Oct 23 2007
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STATUS
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approved
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