cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A269258 Primes p such that p+2^4, p+2^6, p+2^8 and p+2^10 are all primes.

Original entry on oeis.org

7, 37, 163, 337, 2647, 5023, 9157, 9277, 15667, 22093, 24907, 40177, 43597, 47287, 53593, 56893, 59077, 59497, 66553, 78877, 83407, 84793, 92737, 93307, 102043, 111577, 114577, 116953, 120607, 135193, 137383, 141397, 142543, 150067, 165463, 173713, 180007, 181903, 183943
Offset: 1

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Author

Keywords

Examples

			The prime 7 is in the sequence because 7+16 = 23, 7+64 = 71, 7+256 = 263 and 7+1024 = 1031 are all primes.
The prime 37 is in the sequence because 37+16 = 53, 37+64 = 101, 37+256 = 293 and 37+1024 = 1061 are all primes.
		

Crossrefs

Subsequence of A269257.

Programs

  • Magma
    [p: p in PrimesInInterval(2,200000) | forall{i: i in [16,64,256,1024] | IsPrime(p+i)}]; // Vincenzo Librandi, Jul 16 2016
  • Mathematica
    Select[Prime@ Range[10^5], Times @@ Boole@ PrimeQ[# + 2^{4, 6, 8, 10}] == 1 &] (* Michael De Vlieger, Jul 13 2016 *)
  • Perl
    use ntheory ":all"; say for sieve_prime_cluster(2,1e5, 16,64,256,1024); # Dana Jacobsen, Jul 13 2016
    

Formula

A269257 INTERSECT A361485. - R. J. Mathar, Mar 26 2024

A361483 Primes p such that p + 256 is also prime.

Original entry on oeis.org

7, 13, 37, 61, 97, 103, 127, 163, 193, 211, 223, 307, 313, 331, 337, 397, 421, 463, 487, 541, 571, 601, 607, 631, 673, 691, 727, 757, 853, 907, 937, 967, 1021, 1033, 1051, 1063, 1117, 1153, 1171, 1231, 1237, 1297, 1303, 1327, 1381, 1453, 1531, 1567, 1621, 1657, 1693, 1723
Offset: 1

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Author

Elmo R. Oliveira, Mar 13 2023

Keywords

Comments

All terms are == 1 (mod 6).

Examples

			61 and 61 + 256 = 317 are both prime.
		

Crossrefs

Cf. A000040.
Cf. sequences of the type p + k are primes: A001359 (k = 2), A023200 (k = 4), A023202 (k = 8), A049488 (k = 16), A049489 (k = 32), A049490 (k = 64), A049491 (k = 128), this sequence (k = 256), A361484 (k = 512), A361485 (k = 1024).

A361484 Primes p such that p + 512 is also prime.

Original entry on oeis.org

11, 29, 59, 89, 101, 107, 131, 149, 179, 197, 227, 239, 257, 311, 317, 347, 479, 509, 521, 557, 617, 641, 659, 701, 719, 809, 887, 911, 941, 947, 971, 977, 1019, 1031, 1097, 1109, 1151, 1181, 1187, 1229, 1277, 1289, 1319, 1361, 1367, 1439, 1481, 1487, 1499, 1571, 1601
Offset: 1

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Author

Elmo R. Oliveira, Mar 13 2023

Keywords

Comments

All terms are == 5 (mod 6).

Examples

			59 and 59 + 512 = 571 are both prime.
		

Crossrefs

Cf. A000040.
Cf. sequences of the type p + k are primes: A001359 (k = 2), A023200 (k = 4), A023202 (k = 8), A049488 (k = 16), A049489 (k = 32), A049490 (k = 64), A049491 (k = 128), A361483 (k = 256), this sequence (k = 512), A361485 (k = 1024).

A361679 A(n,k) is the n-th prime p such that p + 2^k is also prime; square array A(n,k), n>=1, k>=1, read by antidiagonals.

Original entry on oeis.org

3, 3, 5, 3, 7, 11, 3, 5, 13, 17, 5, 7, 11, 19, 29, 3, 11, 13, 23, 37, 41, 3, 7, 29, 31, 29, 43, 59, 7, 11, 19, 41, 37, 53, 67, 71, 11, 13, 23, 37, 47, 43, 59, 79, 101, 7, 29, 37, 29, 43, 71, 67, 71, 97, 107, 5, 37, 59, 61, 53, 67, 107, 73, 89, 103, 137
Offset: 1

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Author

Alois P. Heinz, Mar 20 2023

Keywords

Examples

			Square array A(n,k) begins:
    3,   3,   3,   3,   5,   3,   3,   7,  11,   7, ...
    5,   7,   5,   7,  11,   7,  11,  13,  29,  37, ...
   11,  13,  11,  13,  29,  19,  23,  37,  59,  67, ...
   17,  19,  23,  31,  41,  37,  29,  61,  89,  73, ...
   29,  37,  29,  37,  47,  43,  53,  97, 101,  79, ...
   41,  43,  53,  43,  71,  67,  71, 103, 107, 127, ...
   59,  67,  59,  67, 107,  73,  83, 127, 131, 139, ...
   71,  79,  71,  73, 131, 103, 101, 163, 149, 157, ...
  101,  97,  89,  97, 149, 109, 113, 193, 179, 163, ...
  107, 103, 101, 151, 167, 127, 149, 211, 197, 193, ...
		

Crossrefs

Row n=1 gives A056206.
Main diagonal gives A361680.
Cf. A000040.

Programs

  • Maple
    A:= proc() option remember; local f; f:= proc() [] end;
          proc(n, k) option remember; local p;
            p:= `if`(nops(f(k))=0, 1, f(k)[-1]);
            while nops(f(k))
    				
Showing 1-4 of 4 results.