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Search: id:A122552
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| A122552 |
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a(0)=a(1)=a(2)=1, a(n)=a(n-1)+a(n-2)+2*a(n-2) for n>2. |
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+0
3
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| 1, 1, 1, 4, 7, 13, 28, 55, 109, 220, 439, 877, 1756, 3511, 7021, 14044, 28087, 56173, 112348, 224695, 449389, 898780, 1797559, 3595117, 7190236, 14380471, 28760941, 57521884, 115043767, 230087533, 460175068, 920350135, 1840700269, 3681400540
(list; graph; listen)
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OFFSET
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0,4
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FORMULA
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a(3*n)=2*a(3*n-1)+2, a(3*n+1)=2*a(3*n)-1, a(3*n+2)=2*a(3*n+1)-1, a(0)=1 . G.f. : (1-x^2)/(1-x-x^2-2*x^3).
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CROSSREFS
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Adjacent sequences: A122549 A122550 A122551 this_sequence A122553 A122554 A122555
Sequence in context: A074864 A074865 A072683 this_sequence A074862 A101064 A055675
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KEYWORD
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nonn
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AUTHOR
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Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Sep 20 2006
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EXTENSIONS
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Corrected by T. D. Noe (noe(AT)sspectra.com), Nov 01 2006
Corrected by T. D. Noe (noe(AT)sspectra.com), Nov 07 2006
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