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Search: id:A123635
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| A123635 |
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Residue mod 3 of average of n-th and (n+1)st odd primes. |
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+0
1
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| 1, 0, 0, 0, 0, 0, 0, 2, 0, 1, 0, 0, 0, 2, 2, 0, 1, 0, 0, 1, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 1, 1, 0, 2, 2, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 2, 0, 0, 2, 2, 2, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 1, 1, 0, 2, 0, 0, 0, 0, 0, 0, 0, 1, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 2, 2, 0, 1, 1, 0, 2, 2, 0, 1, 0
(list; graph; listen)
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OFFSET
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1,8
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FORMULA
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a(n) = (p(n)+p(n+1))/2 mod 3, where p(n) = n-th odd prime.
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EXAMPLE
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Odd primes: 3,5,7,11,13,17,23,...
Averages: (3+5)/2, (5+7)/2, (7+11)/2, ...
Residues mod 3: 1, 0, 0, 0, 0, 0, 0, 2, ...
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MATHEMATICA
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f[n_] := Mod[Prime[n + 1] + Prime[n + 2], 6]/2; Array[f, 105}] (* Robert G. Wilson v Oct 07 2006 *)
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CROSSREFS
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Cf. A065091.
Sequence in context: A034876 A091393 A110270 this_sequence A124304 A165408 A089812
Adjacent sequences: A123632 A123633 A123634 this_sequence A123636 A123637 A123638
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KEYWORD
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easy,nonn
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AUTHOR
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Clark Kimberling (ck6(AT)evansville.edu), Oct 03 2006
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