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A155197
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a(n)=8*a(n-1)+a(n-2), n>2 ; a(0)=1, a(1)=7, a(2)=56 .
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1
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1, 7, 56, 455, 3696, 30023, 243880, 1981063, 16092384, 130720135, 1061853464, 8625547847, 70066236240, 569155437767, 4623309738376, 37555633344775, 305068376496576, 2478102645317383, 20129889539035640, 163517218957602503
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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FORMULA
| G.f.: (1-x-x^2)/(1-8*x-x^2).
a(n)=(14/17)*sqrt(17)*{[4+sqrt(17)]^n-[4-sqrt(17)]^n}+(7/2)*{[4+sqrt(17)]^n+[4-sqrt(17)]^n}+[C(2*n,n) mod 2], with n>=0 [From Paolo P. Lava (paoloplava(AT)gmail.com), Jan 26 2009]
a(n) = Sum_{k, 0<=k<=n} A155161(n,k)*7^k. - DELEHAM Philippe, Feb 08 2012
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CROSSREFS
| Sequence in context: A156362 A055274 A152776 * A147839 A126694 A024091
Adjacent sequences: A155194 A155195 A155196 * A155198 A155199 A155200
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KEYWORD
| nonn,easy,changed
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AUTHOR
| Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jan 21 2009
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