OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..3547 (terms below 10^13 calculated from the b-file at A001274; terms 1..75 from Harry J. Smith, terms 76..1000 from Donovan Johnson)
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
KEYWORD
nonn
AUTHOR
Jason Earls, Aug 13 2001
STATUS
approved