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A133648
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a(n) = 2*3^n + 3^(n-1) - (n+1).
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2
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5, 18, 59, 184, 561, 1694, 5095, 15300, 45917, 137770, 413331, 1240016, 3720073, 11160246, 33480767, 100442332, 301327029, 903981122, 2711943403, 8135830248, 24407490785, 73222472398, 219667417239, 659002251764, 1977006755341
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Inverse binomial transform of A133648 = A133649.
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FORMULA
| O.g.f.: -x*(5-7*x+4*x^2)/[(-1+x)^2*(-1+3*x)] . - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 07 2008
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EXAMPLE
| a(3) = 2*3^3 + 3^2 - 4 = 2*27 + 9 - 4.
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MATHEMATICA
| Table[2*3^n + 3^(n - 1) - (n + 1), {n, 1, 50}] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Sep 20 2007
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CROSSREFS
| Cf. A000244, A133649.
Sequence in context: A190163 A000340 A034567 * A099449 A104630 A062809
Adjacent sequences: A133645 A133646 A133647 * A133649 A133650 A133651
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KEYWORD
| nonn
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AUTHOR
| Gary W. Adamson (qntmpkt(AT)yahoo.com), Sep 19 2007
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EXTENSIONS
| More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Sep 20 2007
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