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A090739 Exponent of 2 in -1+3^(2n). 10
3, 4, 3, 5, 3, 4, 3, 6, 3, 4, 3, 5, 3, 4, 3, 7, 3, 4, 3, 5, 3, 4, 3, 6, 3, 4, 3, 5, 3, 4, 3, 8, 3, 4, 3, 5, 3, 4, 3, 6, 3, 4, 3, 5, 3, 4, 3, 7, 3, 4, 3, 5, 3, 4, 3, 6, 3, 4, 3, 5, 3, 4, 3, 9, 3, 4, 3, 5, 3, 4 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

FORMULA

a(n) = A007814(n) + 3.

EXAMPLE

n=2: -1+3^4=16.5 so a(2)=4.

MATHEMATICA

Table[Part[Flatten[FactorInteger[ -1+3^(2*n)]], 2], {n, 1, 70}]

CROSSREFS

Cf. A069895, A091512, A088660.

Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Jun 18 2009: (Start)

Appears in A161737.

(End)

Sequence in context: A072942 A025267 A201420 * A076400 A121889 A205692

Adjacent sequences:  A090736 A090737 A090738 * A090740 A090741 A090742

KEYWORD

nonn

AUTHOR

Labos E. and R. Stephan ((labos(AT)ana.sote.hu) and (ralf(AT)ark.in-berlin.de)), Jan 19 2004

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Last modified February 14 13:08 EST 2012. Contains 205623 sequences.