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Search: id:A047241
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| A047241 |
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Numbers that are congruent to {1, 3} mod 6. |
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+0
10
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| 1, 3, 7, 9, 13, 15, 19, 21, 25, 27, 31, 33, 37, 39, 43, 45, 49, 51, 55, 57, 61, 63, 67, 69, 73, 75, 79, 81, 85, 87, 91, 93, 97, 99, 103, 105, 109, 111, 115, 117, 121, 123, 127, 129, 133, 135, 139, 141, 145, 147, 151, 153, 157, 159, 163, 165, 169, 171, 175, 177, 181
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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G.f.: (1+2x+3x^2)/((1+x)(1-x)^2)=(1+2x+3x^2)/((1-x)(1-x^2)); E.g.f.: (6x+1)exp(x)/2+exp(-x)/2; a(n)=3n+1/2+(-1)^n/2. - Paul Barry (pbarry(AT)wit.ie), Sep 04 2003
a(n)=6*n-a(n-1)-8 (with a(1)=1) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 22 2009]
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EXAMPLE
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For n=2. a(2)=6*2-1-8=3; n=3, a(3)=6*3-3-8=7; n=4, a(4)=6*4-7-8=9 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 22 2009]
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CROSSREFS
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Sequence in context: A110404 A087064 A087550 this_sequence A086515 A132222 A111225
Adjacent sequences: A047238 A047239 A047240 this_sequence A047242 A047243 A047244
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KEYWORD
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nonn,new
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jul 04 2000
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