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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
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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; refs; listen; history; internal format)
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OFFSET
| 1,8
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FORMULA
| a(n) = (p(n)+p(n+1))/2 mod 3, where p(n) = n-th odd prime.
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EXAMPLE
| 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
| 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
| Cf. A065091.
Sequence in context: A110270 A187143 A187144 * A124304 A165408 A171368
Adjacent sequences: A123632 A123633 A123634 * A123636 A123637 A123638
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KEYWORD
| easy,nonn
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AUTHOR
| Clark Kimberling (ck6(AT)evansville.edu), Oct 03 2006
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