A062568
a(n) is the smallest n-digit strong pseudoprime (in base 2).
Original entry on oeis.org
2047, 15841, 104653, 1004653, 10323769, 100463443, 1002261781, 10000321321, 100004790097, 1000002977551, 10000130243671, 100002236680837, 1000003918690669, 10000008250001701, 100000150553089531, 1000000274500018837, 10000003599249373469
Offset: 4
a(1)=2047 because 2047 is the smallest 4-digit strong pseudoprime to base 2.
A067845
Largest n-digit pseudoprime (to base 2).
Original entry on oeis.org
645, 8911, 93961, 997633, 9995671, 99971821, 999828727, 9999109081, 99983971501, 999986341201, 9999946514845, 99999856404001, 999994510007533, 9999999191658001, 99999984319096601, 999999995115616561, 9999999995077192591
Offset: 3
a(2)=8911, so largest pseudoprime (base 2) of 4 digits is 8911.
A068216
a(n) is the smallest n-digit pseudoprime (to base 2).
Original entry on oeis.org
341, 1105, 10261, 101101, 1004653, 10004681, 100017223, 1001152801, 10000321321, 100004790097, 1000001376901, 10000130243671, 100000105970311, 1000000191735161, 10000006286491369, 100000010102756401, 1000000114865704261, 10000000494514450733
Offset: 3
A048123
Smallest n-digit Carmichael numbers.
Original entry on oeis.org
561, 1105, 10585, 101101, 1024651, 10024561, 100427041, 1001152801, 10017089857, 100023777217, 1000151515441, 10000879761601, 100000782192961, 1000040508690301, 10000092861302401, 100001371359120001, 1000004296444433281, 10000011591390633121
Offset: 3
a(4)=1105 because 1105 is the smallest 4-digit Carmichael number. [corrected by _Jon E. Schoenfield_, Jan 28 2014]
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CarmichaelNbrQ[n_] := ! PrimeQ@ n && Mod[n, CarmichaelLambda@ n] == 1; f[n_] := Block[{k = 10^(n - 1) + 1}, While[! CarmichaelNbrQ@ k, k += 2]; k]; Do[ Print[{n, f[n] // Timing}], {n, 3, 18}]
A063400
Largest n-digit Carmichael numbers.
Original entry on oeis.org
561, 8911, 75361, 997633, 9890881, 99861985, 993905641, 9999109081, 99976607641, 999629786233, 9999501351841, 99994742993377, 999922265173441, 9999924433632001, 99999201310035841, 999996386511276505, 9999998594193164041
Offset: 3
a(4)=8911 because 8911 is the largest 4-digit Carmichael number. [corrected by _Jon E. Schoenfield_, Jan 28 2014]
-
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 *)
Showing 1-5 of 5 results.