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Search: id:A115341
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A115341 a(n) = |A154879(n+1)|. +0
17
2, 4, 0, 8, 8, 24, 40, 88, 168, 344, 680, 1368, 2728, 5464, 10920, 21848, 43688, 87384, 174760, 349528, 699048, 1398104, 2796200, 5592408, 11184808, 22369624, 44739240, 89478488, 178956968, 357913944, 715827880, 1431655768, 2863311528 (list; graph; listen)
OFFSET

0,1

COMMENT

General form: a(n)=2^n-a(n-1). Also: A001045, A078008, A097073 [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Dec 11 2008]

FORMULA

a(n) = (2^(n+1)-8*(-1)^n)/3, n>0.

a(n) = a(n-1)+2*a(n-2), n>2. G.f.: 2+4*x*(-1+x)/((1+x)*(2*x-1)).

MATHEMATICA

g0[n_] = 2 - Sum[(-1)^(i + 1)/Sqrt[2]^(2*i), {i, 0, n}] f[x_] = ZTransform[g0[n], n, x] g[n_] = InverseZTransform[f[1/x], x, n] a0 = Table[Abs[g[n]], {n, 1, 25}]

k=0; lst={k}; Do[k=2^n-k; AppendTo[lst, k], {n, 3, 5!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Dec 11 2008]

CROSSREFS

Cf. A001045, A078008, A097073 [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Dec 11 2008]

Sequence in context: A099890 A137511 A011166 this_sequence A101160 A103191 A071607

Adjacent sequences: A115338 A115339 A115340 this_sequence A115342 A115343 A115344

KEYWORD

nonn

AUTHOR

Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Mar 06 2006

EXTENSIONS

Edited by the Associate Editors of the OEIS, Aug 21 2009

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Last modified November 24 23:16 EST 2009. Contains 167481 sequences.


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