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A063739 Squarefree n such that phi(n) = phi(n+1). 1
1, 3, 15, 194, 255, 2834, 3255, 3705, 5186, 5187, 11715, 22935, 25545, 49215, 49335, 65535, 214334, 256274, 388245, 525986, 568815, 589407, 840255, 936494, 1259642, 1574727, 1659585, 1759874, 1788254, 2123583, 2200694, 2521694, 2619705, 3240614, 3289934 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harry J. Smith and Donovan Johnson, Table of n, a(n) for n = 1..1000 (first 75 terms from Harry J. Smith)

MATHEMATICA

Select[Range[3000000], SquareFreeQ[#]&&EulerPhi[#]==EulerPhi[#+1]&] (* Harvey P. Dale, May 15 2013 *)

PROG

(PARI) for(n=1, 10^7, if(issquarefree(n), if(eulerphi(n)==eulerphi(n+1), print(n))))

(PARI) { n=0; for (m=1, 10^9, if (eulerphi(m)==eulerphi(m + 1) && issquarefree(m), write("b063739.txt", n++, " ", m); if (n==75, break)) ) } \\ Harry J. Smith, Aug 29 2009

CROSSREFS

Cf. A005117, A001274.

Sequence in context: A173301 A260079 A087614 * A060194 A068858 A280772

Adjacent sequences:  A063736 A063737 A063738 * A063740 A063741 A063742

KEYWORD

nonn

AUTHOR

Jason Earls, Aug 13 2001

STATUS

approved

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Last modified November 18 04:44 EST 2019. Contains 329248 sequences. (Running on oeis4.)