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A127904 Smallest m such that A008687(m) = n. 3
0, 1, 3, 5, 9, 17, 33, 65, 129, 257, 513, 1025, 2049, 4097, 8193, 16385, 32769, 65537, 131073, 262145, 524289, 1048577, 2097153, 4194305, 8388609, 16777217, 33554433, 67108865, 134217729, 268435457, 536870913, 1073741825, 2147483649 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

A008687(a(n)) = n and A008687(m) < n for m < a(n).

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (3,-2).

FORMULA

For n>1, a(n) = A000051(n-1) = 2^(n-1)+1.

G.f.: x*(1-2*x^2)/((1-x)*(1-2*x)). a(n) = 3*a(n-1)-2*a(n-2) for n=2 and n>3. - Bruno Berselli, Sep 01 2011

MATHEMATICA

Join[{0, 1}, LinearRecurrence[{3, -2}, {3, 5}, 40]] (* or *) Join[{0, 1}, 2^Range[ 40]+1] (* Harvey P. Dale, Jan 16 2013 *)

CROSSREFS

Sequence in context: A205537 A135728 A083318 * A048578 A087312 A099170

Adjacent sequences:  A127901 A127902 A127903 * A127905 A127906 A127907

KEYWORD

nonn,easy

AUTHOR

Reinhard Zumkeller, Feb 05 2007

STATUS

approved

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Last modified August 18 19:41 EDT 2017. Contains 290762 sequences.