A218710 a(n) is smallest number such that a(n)^2 + 1 is divisible by 17^n.

0, 4, 38, 1985, 27493, 390112, 390112, 96940388, 3379649772, 24306922095, 450044583893, 5597937117454, 28673959190179, 3524407382568745, 13428985415474682, 13428985415474682, 5711417117604156904, 91610966633729580058, 6709533061724423693474

Offset

0,2

Links

Table of n, a(n) for n=0..18.

Example

a(4) = 27493 because 27493^2+1 =  2 * 5 ^ 2 * 17 ^ 4 * 181.

Mathematica

b=4; n17=17; jo=Join[{0, b}, Table[n17=17*n17; b=PowerMod[b, 17, n17]; b=Min[b, n17-b], {99}]]

Crossrefs

Cf. A002522, A049532, A034939, A218709.

Sequence in context: A178017 A131591 A030259 * A286877 A373826 A018860

Adjacent sequences: A218707 A218708 A218709 * A218711 A218712 A218713

Keyword

nonn

Author

Michel Lagneau, Nov 04 2012

Status

approved