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Search: id:A047471
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| A047471 |
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Numbers that are congruent to {1, 3} mod 8. |
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+0
2
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| 1, 3, 9, 11, 17, 19, 25, 27, 33, 35, 41, 43, 49, 51, 57, 59, 65, 67, 73, 75, 81, 83, 89, 91, 97, 99, 105, 107, 113, 115, 121, 123, 129, 131, 137, 139, 145, 147, 153, 155, 161, 163, 169, 171, 177, 179, 185, 187, 193
(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+5x^2)/((1+x)(1-x)^2); a(n)=4n+(-1)^n; - Paul Barry (pbarry(AT)wit.ie), Apr 10 2008
a(n)=4*(n-1)-(-1)^n [From Rolf Pleisch (r_pleisch(AT)gmx.ch), Aug 04 2009]
a(n)=8*n-a(n-1)-12 (with a(1)=1) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 24 2009]
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EXAMPLE
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For n=2, a(2)=8*2-1-12=3; n=3, a(3)=8*3-3-12=9; n=4, a(4)=8*4-9-12=11 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 24 2009]
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CROSSREFS
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Sequence in context: A131861 A131859 A096187 this_sequence A157139 A050538 A062227
Adjacent sequences: A047468 A047469 A047470 this_sequence A047472 A047473 A047474
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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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