The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A231475 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A231475

Largest integer less than 5 and coprime to n.
(history; published version)

#20 by Harvey P. Dale at Sat Aug 27 17:58:52 EDT 2022

STATUS

editing

approved

#19 by Harvey P. Dale at Sat Aug 27 17:58:49 EDT 2022

MATHEMATICA

Max[Table[If[CoprimeQ[#, d], d, 0], {d, 4}]]&/@Range[100] (* Harvey P. Dale, Aug 27 2022 *)

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approved

editing

#18 by Harvey P. Dale at Sat Aug 27 17:55:33 EDT 2022

STATUS

editing

approved

#17 by Harvey P. Dale at Sat Aug 27 17:55:30 EDT 2022

EXAMPLE

a(1)=4 because this is the largest integer less than 5 and its it's coprime to n=1.

STATUS

approved

editing

#16 by Alois P. Heinz at Thu Dec 20 18:58:14 EST 2018

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proposed

approved

#15 by Antti Karttunen at Thu Dec 20 18:46:13 EST 2018

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editing

proposed

#14 by Antti Karttunen at Thu Dec 20 17:43:56 EST 2018

LINKS

Antti Karttunen, <a href="/A231475/b231475.txt">Table of n, a(n) for n = 1..65537</a>

FORMULA

a(2k+1) = 4 = 2*2.

a(2k) = 1 if 3|k, otherwise a(2k)=3. - Jon Perry, Nov 09 2013

PROG

(PARI) aA231475(n, m=5) = for(k=1, m, gcd(n, m-k)==1&&return(m-k)));

STATUS

approved

editing

#13 by N. J. A. Sloane at Sun Nov 10 10:58:46 EST 2013

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proposed

approved

#12 by Jon Perry at Sat Nov 09 17:59:46 EST 2013

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editing

proposed

#11 by Jon Perry at Sat Nov 09 17:59:31 EST 2013

LINKS

Wikipedia, <a href="http://en.wikipedia.org/wiki/Greatest_common_divisor">GCD</a>

STATUS

proposed

editing