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A067317
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n is in the sequence if 1+C(n,j) is prime for only 2 values of j (0<=j<=n), where C(n,j) is the binomial coefficient n choose j.
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1
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1, 3, 7, 15, 23, 31, 59, 63, 67, 81, 84, 93, 95, 127, 157, 170, 214, 239, 253, 255, 313, 470, 511, 622, 694, 1010, 1023, 1098, 1691, 2047, 3535, 3836, 3963, 4095
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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FORMULA
| n values for which A067316(n)=2
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EXAMPLE
| The 2 values of j are 0 and n, which give the prime 2. The sequence includes all numbers 2^k-1 since C(2^k-1,j) is odd for all j.
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MATHEMATICA
| test[n_] := Module[{}, For[i=1, 2i<=n, i++, If[PrimeQ[Binomial[n, i]+1], Return[False]]]; True]; For[n=1, True, n++, If[test[n], Print[n]]]
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CROSSREFS
| Cf. A067316.
Sequence in context: A192122 A069119 A187220 * A141354 A181106 A131753
Adjacent sequences: A067314 A067315 A067316 * A067318 A067319 A067320
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KEYWORD
| more,nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Jan 15 2002
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EXTENSIONS
| More terms from Jon E. Schoenfield (jonscho(AT)hiwaay.net), May 30 2010
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