The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A023512 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A023512

Exponent of 2 in prime factorization of prime(n) + 1.
(history; published version)

#28 by Charles R Greathouse IV at Thu Sep 08 08:44:47 EDT 2022

PROG

(MAGMAMagma) [Valuation(NthPrime(n)+1, 2): n in [1..110]]; // Bruno Berselli, Aug 05 2013

Discussion

Thu Sep 08

08:44

OEIS Server: https://oeis.org/edit/global/2944

#27 by N. J. A. Sloane at Tue Apr 19 01:07:31 EDT 2016

EXTENSIONS

Corrected by _Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp), _, Feb 25 2005

Discussion

Tue Apr 19

01:07

OEIS Server: https://oeis.org/edit/global/2496

#26 by N. J. A. Sloane at Fri Apr 25 11:13:39 EDT 2014

STATUS

proposed

approved

#25 by Zak Seidov at Fri Apr 25 08:23:50 EDT 2014

STATUS

editing

proposed

#24 by Zak Seidov at Fri Apr 25 08:23:44 EDT 2014

MATHEMATICA

IntegerExponent[Prime[Range[100]] + 1, 2] (* Zak Seidov, Apr 25 2014 *)

STATUS

approved

editing

#23 by Joerg Arndt at Tue Mar 11 03:26:33 EDT 2014

STATUS

editing

approved

#22 by Joerg Arndt at Tue Mar 11 03:26:24 EDT 2014

PROG

(PARI) a(n)=valuation(prime(n)+1, 2); vector(100, n, a(n)) \\ _Joerg Arndt_, Mar 11 2014

vector(100, n, a(n)) \\ Joerg Arndt, Mar 11 2014

#21 by Joerg Arndt at Tue Mar 11 03:25:35 EDT 2014

MAPLE

with(numtheory): a:=proc(n) local div, s, j, c: div:=divisors(1+ithprime(n)): s:=nops(div): for j from 1 to s do if type(simplify(log[2](div[j])), integer)=true then c[j]:=simplify(log[2](div[j])) else c[j]:=0 fi od: max(seq(c[j], j=1..s)) end: seq(a(n), n=1..120); # most probably not the simplest Maple program (_- _Emeric Deutsch_, Jul 20 2005)

MATHEMATICA

Join[{0}, Table[FactorInteger[Prime[n] + 1][[1]][[2]], {n, 2, 100}]] (* _Clark Kimberling, _, Oct 01 2013 *)

PROG

(PARI) a(n)=valuation(prime(n)+1, 2); vector(100, n, a(n)) \\ Joerg Arndt, Mar 11 2014

STATUS

proposed

editing

#20 by Michel Marcus at Mon Mar 10 13:08:25 EDT 2014

STATUS

editing

proposed

#19 by Michel Marcus at Mon Mar 10 13:08:21 EDT 2014

CROSSREFS

Cf. A239114.

STATUS

proposed

editing