A165887 - OEIS

A165887

Numbers n such that x^4 + y^4 != 0 (mod n) when both x, y (positive) are expressed mod n (i.e., 0 < x,y < n).

3, 5, 7, 11, 13, 15, 19, 21, 23, 29, 31, 33, 35, 37, 39, 43, 47, 53, 55, 57, 59, 61, 65, 67, 69, 71, 77, 79, 83, 87, 91, 93, 95, 101, 103, 105, 107, 109, 111, 115, 127, 129, 131, 133, 139, 141, 143, 145, 149, 151, 155, 157, 159, 161, 163, 165, 167, 173, 177, 179, 181

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Example a(5)=13 since x^4 + y^4 = 13k (k being a natural number) has no integer solutions 0 < x,y < 13.

LINKS

Table of n, a(n) for n=1..61.

CROSSREFS

Sequence in context: A141107 A047484 A036991 * A316625 A091892 A292939

Adjacent sequences: A165884 A165885 A165886 * A165888 A165889 A165890

KEYWORD

nonn

AUTHOR

Carmine Suriano, Sep 29 2009

EXTENSIONS

Value 11 in the example corrected to 13 by Carmine Suriano, Oct 07 2009

STATUS

approved