A063400 Largest n-digit Carmichael numbers.

561, 8911, 75361, 997633, 9890881, 99861985, 993905641, 9999109081, 99976607641, 999629786233, 9999501351841, 99994742993377, 999922265173441, 9999924433632001, 99999201310035841, 999996386511276505, 9999998594193164041

Offset

3,1

Links

Table of n, a(n) for n=3..19.

Example

a(4)=8911 because 8911 is the largest 4-digit Carmichael number. [corrected by Jon E. Schoenfield, Jan 28 2014]

Mathematica

CarmichaelNbrQ[n_] := !PrimeQ[n] && Mod[n, CarmichaelLambda[n]] == 1; f[n_] := f[n] = Block[{k = 10^n - 1}, While[!CarmichaelNbrQ[k], k -= 2]; k]; Reap[Do[Print[{n, f[n]}]; Sow[f[n]], {n, 3, 10}]][[2, 1]] (* Jean-François Alcover, Jan 28 2014, after Shyam Sunder Gupta *)

Crossrefs

Cf. A062568, A062852, A048123.

Sequence in context: A207080 A339875 A290945 * A141706 A290485 A213071

Adjacent sequences: A063397 A063398 A063399 * A063401 A063402 A063403

Keyword

hard,more,nonn,base

Author

Shyam Sunder Gupta, Feb 17 2002

Extensions

a(17)-a(19) from Amiram Eldar, Jun 29 2019

Status

approved