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A245522
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Index of the smallest prime where n consecutive trailing digits of the index written in binary match n consecutive trailing digits in the prime when written in binary.
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3
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3, 11, 15, 15, 31, 39, 373, 1285, 1285, 1285, 2119, 2119, 15605, 29223, 52225, 52225, 186157, 186157, 1378927, 3137489, 4189897, 4189897, 10373543, 50359121, 50359121, 50359121, 490844965, 605616359, 605616359, 605616359, 3351375815, 3351375815, 5812974437
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OFFSET
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1,1
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COMMENTS
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Similar to A133589, except the comparison is done in binary.
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LINKS
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EXAMPLE
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a(6) = 39 since 39 in binary is 100111, the 39th prime is 167, or 10100111 in binary and the last 6 digits of these two binary numbers coincide.
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MATHEMATICA
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f[n_] := Module[{p = Prime[n]}, m = IntegerExponent[p - n, 2]; If[n < 2^m, Length[IntegerDigits[n, 2]], m]]; fm = 0; s = {}; Do[f1 = f[n]; If[f1 > fm, s = Join[s, Table[n, {f1 - fm}]]; fm = f1], {n, 1, 10^6}]; s (* Amiram Eldar, May 13 2019 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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