A062308
Largest prime factor of 11^n+1 (A034524).
Original entry on oeis.org
2, 3, 61, 37, 7321, 13421, 1117, 1623931, 6304673, 590077, 212601841, 58367, 20113, 59583967, 55527473, 7537711, 447600088289, 2218331, 3138426605161, 1390636259, 1120648576818041, 3421169496361, 2649263870814793
Offset: 0
Cf. similar sequences listed in
A274903.
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[Maximum(PrimeDivisors(11^n+1)): n in [0..40]]; // Vincenzo Librandi, Jul 12 2016
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Table[FactorInteger[11^n + 1][[-1, 1]], {n, 0, 20}] (* Vincenzo Librandi, Jul 12 2016 *)
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for(n=0,22,print(factor(11^n+1)))
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{ for (n=0, 80, f=factor(11^n + 1)~; write("b062308.txt", n, " ", f[1, length(f)]) ) } \\ Harry J. Smith, Aug 04 2009
a(302)-a(325) in b-file from
Max Alekseyev, Apr 25 2022, Oct 11 2023
A366720
Largest prime factor of 12^n+1.
Original entry on oeis.org
2, 13, 29, 19, 233, 19141, 20593, 13063, 260753, 1801, 85403261, 57154490053, 2227777, 222379, 13156924369, 35671, 1200913648289, 66900193189411, 122138321401, 905265296671, 67657441, 1885339, 68368660537, 49489630860836437, 592734049, 438472201
Offset: 0
Cf.
A178248,
A006530,
A002587,
A074476,
A274903,
A074478,
A274904,
A227575,
A274905,
A002592,
A003021,
A062308,
A002590,
A366712,
A366713,
A366714,
A366715,
A366716,
A366717,
A366718,
A366719,
A324941.
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Table[FactorInteger[12^n + 1][[-1, 1]], {n, 0, 20}]
A274904
Largest prime factor of 6^n + 1.
Original entry on oeis.org
2, 7, 37, 31, 1297, 101, 97, 197, 98801, 46441, 6781, 51828151, 1678321, 37571, 5030761, 1950271, 4709377, 12690943, 55117, 48713705333, 68754507401, 2527867231, 863017, 990000731, 473896897, 3655688315536801, 6291946695217, 883383463, 81035189089
Offset: 0
6^3 + 1 = 217 = 7*31, so a(3) = 31.
Cf. similar sequences listed in
A274903.
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[Maximum(PrimeDivisors(6^n+1)): n in [0..40]];
-
Table[FactorInteger[6^n + 1][[-1, 1]], {n, 0, 40}]
a(409)-a(430) in b-file from
Max Alekseyev, Apr 25 2022, Apr 15 2025
A229747
Largest prime factor of 4^(2*n+1)+1.
Original entry on oeis.org
5, 13, 41, 113, 109, 2113, 1613, 1321, 26317, 525313, 14449, 30269, 268501, 279073, 536903681, 384773, 4327489, 47392381, 231769777, 21841, 43249589, 1759217765581, 29247661, 140737471578113, 4981857697937, 1326700741, 1801439824104653, 3630105520141
Offset: 0
For n=7, 4^(2*n+1)+1 = 1073741825 = 5*5*13*41*61*1321. So a(7)=1321.
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Table[FactorInteger[4^(2n+1)+1][[-1,1]],{n,0,30}] (* Harvey P. Dale, Mar 10 2018 *)
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a(n) = {
f=factor(2^(2*n+1)-2^(n+1)+1);
g=factor(2^(2*n+1)+2^(n+1)+1);
max(f[matsize(f)[1],1], g[matsize(g)[1],1])
}
A324941
Largest prime factor of 17^n + 1.
Original entry on oeis.org
2, 3, 29, 13, 41761, 101, 83233, 22796593, 184417, 5653, 63541, 87415373, 72337, 2001793, 100688449, 238212511, 52548582913, 45957792327018709121, 382069, 20352763, 1186844128302568601, 88109799136087, 6901823633, 1109309383381084655697725873, 48661191868691111041
Offset: 0
Cf.
A002587,
A074476,
A274903,
A074478,
A274904,
A227575,
A274905,
A002592,
A003021,
A062308,
A002590.
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[Maximum(PrimeDivisors(17^n + 1)): n in [0..40]];
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Table[FactorInteger[17^n + 1] [[-1,1]], {n, 0, 30}]
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a(n) = vecmax(factor(17^n+1)[, 1]); \\ Jinyuan Wang, Apr 05 2019
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