A177496 a(n) is the least k such that the remainder when 1000^k is divided by k is n.

3, 62, 997, 6, 115, 7, 51, 14, 991, 11, 23, 13, 21, 17, 197, 24, 983, 158, 109, 35, 89, 42, 977, 61, 39, 34, 139, 36, 971, 38, 3291, 188, 967, 66, 193, 92, 57, 74, 999161, 52, 137, 479, 69, 239, 191, 53, 953, 49, 317, 70, 73, 79, 947, 65291, 63, 59, 448991, 114, 941

Offset: 1

Author

Alexander Adamchuk, May 10 2010

Keywords

• nonn

Crossrefs

Cf. A036236, A078457, A119678, A119679, A127816, A119715, A119714, A127817, A127818, A127819, A127820, A127821, A128154, A128155, A128156, A128157, A128158, A128159, A128160, A128361, A128362, A128363, A128364, A128365, A128366, A128367, A128368, A128369, A128370, A128371, A128372, A177495.

Cf. A128149, A128150, A128172.

Programs

Mathematica

t = Table[0, {98}]; k = 1; While[k < 10000000, a = PowerMod[1000, k, k]; If[a < 99 && t[[a]] == 0, t[[a]] = k; Print[{a, k}]]; k++ ]; t
lk[n_]:=Module[{k=1},While[PowerMod[1000,k,k]!=n,k++];k]; Array[lk,60] (* Harvey P. Dale, Jul 21 2021 *)