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4, 5, 7, 11, 19, 35, 67, 131, 259, 515, 1027, 2051, 4099, 8195, 16387, 32771, 65539, 131075, 262147, 524291, 1048579, 2097155, 4194307, 8388611, 16777219, 33554435, 67108867, 134217731, 268435459, 536870915, 1073741827, 2147483651
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| Written in binary a(n) is 1000...00011 for n>1.
For n>=2,a(n)is the minimal k for which A000120(k(2^n-1)) is not multiple of n. [From Vladimir Shevelev (shevelev(AT)bgu.ac.il), Jun 05 2009]
a(n) = A173921(A000051(n+1)). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 04 2010]
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index to sequences with linear recurrences with constant coefficients, signature (3,-2).
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FORMULA
| a(n) = 2a(n-1)-3 = A052548(n)+1 = A000051(n)+2 = A000079(n)+3 = A000225(n)+4 = A030101(A004119(n)) for n>1. G.f.: (4-7*x)/((1-2*x)*(1-x)).
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MATHEMATICA
| a[n_]:=2^n+3; ...and/or...a=4; lst={a}; Do[a=(a-1)*2-1; AppendTo[lst, a], {n, 5!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Jan 03 2009]
LinearRecurrence[{3, -2}, {4, 5}, 40] (* Vincenzo Librandi, Jan 31 2012 *)
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PROG
| (Other) sage: [gaussian_binomial(n, 1, 2)+4 for n in xrange(0, 32)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 31 2009]
(PARI) a(n)=2^n+3 \\ Charles R Greathouse IV, Jan 30 2012
(MAGMA) [2^n+3: n in [0..40]] // Vincenzo Librandi, Jan 31 2012
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CROSSREFS
| Primes in this sequence are A057733.
Sequence in context: A175903 A080327 A184778 * A129302 A051658 A047491
Adjacent sequences: A062706 A062707 A062708 * A062710 A062711 A062712
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KEYWORD
| nonn,easy
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AUTHOR
| Henry Bottomley (se16(AT)btinternet.com), Jul 13 2001
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