

A066499


Numbers k such that phi(k) == 2 (mod 4).


8



3, 4, 6, 7, 9, 11, 14, 18, 19, 22, 23, 27, 31, 38, 43, 46, 47, 49, 54, 59, 62, 67, 71, 79, 81, 83, 86, 94, 98, 103, 107, 118, 121, 127, 131, 134, 139, 142, 151, 158, 162, 163, 166, 167, 179, 191, 199, 206, 211, 214, 223, 227, 239, 242, 243, 251, 254, 262, 263, 271
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Related to the equation x^4 = 1 (mod y): sequence gives values of n such x^4 = 1 (mod n) has no solution 1 < x < n1.
k is of the form p^m or 2*p^m where p is A002145 (with the exception of a(2)=4).


REFERENCES

W. J. LeVeque, Fundamentals of Number Theory, pp. 57 Problem 15, Dover NY 1996.


LINKS



MATHEMATICA

Select[Range[300], Mod[EulerPhi[#], 4]==2&] (* Harvey P. Dale, Feb 18 2018 *)


PROG

(PARI) { n=0; for (m=1, 10^10, if (eulerphi(m)%4 == 2, write("b066499.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Feb 18 2010


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



