A155941
Numbers n such that 16*n+1 is not prime.
Original entry on oeis.org
0, 2, 3, 4, 5, 8, 9, 10, 11, 13, 14, 17, 18, 19, 20, 23, 24, 26, 29, 30, 31, 32, 33, 34, 35, 38, 39, 41, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 56, 57, 59, 60, 62, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 77, 79, 80, 82, 83, 84, 86, 87, 89, 90, 91, 92, 94, 95
Offset: 1
Distribution of a(n)>0 in the following triangular array:
*;
*,*;
*,*,3;
*,*,*,5;
2,*,*,*,*;
*,4,*,*,*,*;
*,*,*,*,*,*,14;
*,*,*,*,*,*,*,18;
*,*,*,*,13,*,*,*,*;
*,*,*,*,*,17,*,*,*,*;
*,*,10,*,*,*,*,*,*,*,33;
*,*,*,14,*,*,*,*,*,*,*,39;
5,*,*,*,*,*,*,*,32,*,*,*,*; etc.
where * marks the non-integer values of (2*h*k + k + h)/8 with h >= k >= 1. - _Vincenzo Librandi_, Jan 15 2013
A155942
Numbers n such that 16n+1 is a prime.
Original entry on oeis.org
1, 6, 7, 12, 15, 16, 21, 22, 25, 27, 28, 36, 37, 40, 42, 48, 55, 58, 61, 63, 72, 75, 76, 78, 81, 85, 88, 93, 97, 100, 106, 111, 117, 118, 126, 130, 132, 133, 135, 142, 151, 162, 163, 166, 168, 172, 175, 177, 181, 190, 193, 195, 196, 198, 201, 207, 208, 210, 216, 226
Offset: 1
A228857
Odd primes p > 3 for which 14*p+1 is also prime.
Original entry on oeis.org
5, 17, 47, 53, 59, 83, 107, 113, 149, 167, 173, 239, 269, 353, 419, 443, 449, 503, 509, 563, 587, 599, 647, 659, 677, 719, 797, 827, 929, 947, 977, 983, 1097, 1103, 1109, 1187, 1193, 1223, 1229, 1259, 1289, 1367, 1409, 1427, 1433, 1439, 1493, 1523, 1667
Offset: 1
As both 5 and 14*5 + 1 = 71 are prime, then 5 is a member of this sequence.
- Paulo Ribenboim; Fermat’s Last Theorem For Amateurs, Springer-Verlag, New York, Inc., (1999).
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[p: p in PrimesInInterval(5,2000) |IsPrime(14*p+1)]; // Vincenzo Librandi, Sep 18 2016
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Select[Prime[Range[3,1667]],PrimeQ[14#+1] &]
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lista(nn) = forprime(p=5, nn, if(isprime(14*p+1), print1(p, ", "))); \\ Altug Alkan, Sep 18 2016
A106064
Primes p such that 1*p + 16 and 16*p + 1 are primes.
Original entry on oeis.org
7, 37, 97, 151, 163, 181, 331, 337, 487, 547, 571, 643, 727, 757, 967, 1033, 1087, 1093, 1303, 1423, 1471, 1567, 1831, 1987, 2083, 2113, 2221, 2251, 2281, 2671, 2683, 3121, 3187, 3607, 3847, 3931, 4111, 4201, 4447, 4663, 4993, 5023, 5791, 6073, 6343, 6553
Offset: 1
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[p: p in PrimesUpTo(10000)| IsPrime(p+16) and IsPrime(16*p+1)]; // Vincenzo Librandi, Nov 13 2010
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Select[Prime[Range[220]], PrimeQ[16#+1]&&PrimeQ[1#+16]&]
Showing 1-4 of 4 results.
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