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Search: id:A152224
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| A152224 |
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a(n)=4*a(n-1)+6*a(n-2), n>1 ; a(0)=1, a(1)=6 . |
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+0
2
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| 1, 6, 30, 156, 804, 4152, 21432, 110640, 571152, 2948448, 15220704, 78573504, 405618240, 2093913984, 10809365376, 55800945408, 234013147008, 1270858260480, 6487511923968, 37575197258752, 173225860578816
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OFFSET
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0,2
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COMMENT
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Unsigned version of A152223 .
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FORMULA
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G.F.: (1+2x)/(1-4x-6x^2).
a(n)=(1/2)*{[2+sqrt(10)]^n+[2-sqrt(10)]^n}+(1/5)*sqrt(10)*{[2+sqrt(10)]^n-[2-sqrt(10)]^n}, with n>=0 [From Paolo P. Lava (ppl(AT)spl.at), Dec 12 2008]
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CROSSREFS
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Cf. A152223
Sequence in context: A126474 A127017 A152223 this_sequence A026112 A038155 A026331
Adjacent sequences: A152221 A152222 A152223 this_sequence A152225 A152226 A152227
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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), Nov 29 2008
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