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A048490
a(n) = T(7,n), array T given by A048483.
6
1, 9, 25, 57, 121, 249, 505, 1017, 2041, 4089, 8185, 16377, 32761, 65529, 131065, 262137, 524281, 1048569, 2097145, 4194297, 8388601, 16777209, 33554425, 67108857, 134217721, 268435449, 536870905, 1073741817, 2147483641, 4294967289, 8589934585
OFFSET
0,2
COMMENTS
n-th difference of a(n), a(n-1), ..., a(0) is (8, 8, 8, ...).
FORMULA
a(n) = 8 * 2^n - 7. - Ralf Stephan, Jan 09 2009
Equals binomial transform of [1, 8, 8, 8, ...]. - Gary W. Adamson, Apr 29 2008
a(n) = 2*a(n-1) + 7 for n > 0, a(0)=1. - Vincenzo Librandi, Aug 06 2010
For n>=1, a(n) = 6<+>(n+3), where the operation <+> is defined in A206853. - Vladimir Shevelev, Feb 17 2012
From Colin Barker, Nov 26 2014: (Start)
a(n) = 3*a(n-1) - 2*a(n-2).
G.f.: (6*x+1) / ((x-1)*(2*x-1)). (End)
MATHEMATICA
a=1; lst={a}; k=8; Do[a+=k; AppendTo[lst, a]; k+=k, {n, 0, 5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Dec 16 2008 *)
PROG
(PARI) Vec((6*x+1)/((x-1)*(2*x-1)) + O(x^100)) \\ Colin Barker, Nov 26 2014
CROSSREFS
Sequence in context: A269440 A234038 A304033 * A113828 A099971 A124702
KEYWORD
nonn,easy
EXTENSIONS
More terms from Colin Barker, Nov 26 2014
STATUS
approved