A128683 Numbers k such that k^3 divides 10^(k^2) + 1.

1, 11, 253, 11891, 35167, 45023, 47927, 96569, 276859, 640343, 1035529, 1102321, 1652849, 2221087, 6367757, 16339367, 19588019, 26499979, 30096121, 48669863, 51809087, 74901409, 88023001, 89007677, 104391089, 105080767, 143938531

Offset: 1

Author

Alexander Adamchuk, Mar 31 2007

Keywords

• hard
• nonn

Comments

11 divides a(n) for n > 1.

Links

• Chai Wah Wu, Table of n, a(n) for n = 1..92

Crossrefs

Cf. A127263, A128677, A128678, A128679, A128680, A128681, A128682, A128684, A128685, A292335.

Programs

Mathematica

Select[Range[5*10^6], Mod[ 10^(#^2)+1, #^3]==0 &] (* G. C. Greubel, Jan 18 2018 *)

Extensions

More terms from J. Mulder (jasper.mulder(AT)planet.nl), Jan 26 2010

Terms a(16) onward from Max Alekseyev and Alexander Adamchuk, May 12 2010