The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A245522 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A245522

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.
(history; published version)

#13 by Peter Luschny at Mon May 13 05:24:51 EDT 2019

STATUS

reviewed

approved

#12 by Michel Marcus at Mon May 13 05:24:22 EDT 2019

STATUS

proposed

reviewed

#11 by Amiram Eldar at Mon May 13 05:23:36 EDT 2019

STATUS

editing

proposed

#10 by Amiram Eldar at Mon May 13 05:20:54 EDT 2019

DATA

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

MATHEMATICA

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 *)

KEYWORD

nonn,more,base

EXTENSIONS

a(23)-a(33) from Amiram Eldar, May 13 2019

STATUS

approved

editing

#9 by N. J. A. Sloane at Sat Jul 26 10:31:41 EDT 2014

STATUS

editing

approved

#8 by N. J. A. Sloane at Sat Jul 26 10:31:37 EDT 2014

EXAMPLE

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 2 two binary numbers coincide.

STATUS

proposed

editing

#7 by Michel Marcus at Fri Jul 25 01:38:26 EDT 2014

STATUS

editing

proposed

#6 by Michel Marcus at Fri Jul 25 01:38:09 EDT 2014

COMMENTS

Similar to A133589, except the comparison is done in binary.

CROSSREFS

Cf. A245520, A245521, A245523, A133583, A133584, A133589, A133590. Similar to A133589, except the comparison is done in binary.

STATUS

proposed

editing

Discussion

Fri Jul 25

01:38

Michel Marcus: Moved comment from xrefs to comments

#5 by Chai Wah Wu at Thu Jul 24 21:49:04 EDT 2014

STATUS

editing

proposed

#4 by Chai Wah Wu at Thu Jul 24 21:49:00 EDT 2014

CROSSREFS

Cf. A245520, A245521, A245523, A133583, A133584, A133589, A133590. Similar to A133589, except the comparison is done in binary.

STATUS

proposed

editing