A215738 Odd numbers k which satisfy the congruence 5^(2k-1) == 3^(2k-1) (mod 2k).

1, 473, 8393, 9713, 33583, 68513, 232243, 249293, 343613, 430073, 689623, 1037513, 1519133, 1800293, 2814053, 4436873, 4769083, 6796913, 7056053, 7152233, 11545253, 13637579, 15854333, 16489253, 20336033, 25166383, 37745873, 47778713, 53042693, 58358273, 58719833

Offset

1,2

Comments

Table 1, section a=3, by Paszkiewicz et al.

Links

Table of n, a(n) for n=1..31.

A. Paszkiewicz and A. Rotkiewicz, On a Problem of H. J. A. Duparc, Tatra Mt. Math. Publ. 32 (2005) 15-32, MR2206908.

Maple

filter:= n -> 5 &^ (2*n-1) - 3 &^ (2*n-1) mod (2*n) = 0:
select(filter, [seq(seq(i+30*j, i=[1, 7, 11, 13, 17, 19, 23, 29]), j=0..10^6)]); # Robert Israel, Oct 26 2017

Prog

(Magma) [n: n in [1..70000] | (5^(2*n-1)-3^(2*n-1)) mod (2*n) eq 0]; // Vincenzo Librandi, Oct 26 2017

Crossrefs

Sequence in context: A084629 A075286 A235897 * A348806 A370295 A045302

Adjacent sequences: A215735 A215736 A215737 * A215739 A215740 A215741

Keyword

nonn

Author

R. J. Mathar, Aug 22 2012

Extensions

1 inserted, and more terms added by Robert Israel, Oct 26 2017

Status

approved