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 1-9 of 9 results.

A098974 Primes p such that q-p = 24, where q is the next prime after p.

Original entry on oeis.org

1669, 2179, 4177, 4523, 4759, 5237, 6173, 6397, 6737, 7079, 7369, 7793, 8123, 8329, 9067, 11003, 11633, 11839, 12073, 12119, 13009, 13267, 16033, 16193, 16453, 16763, 16787, 17053, 17683, 17989, 18593, 18637, 19183, 19507, 20483, 22409, 22877, 23227
Offset: 1

Views

Author

Douglas Winston (douglas.winston(AT)srupc.com), Oct 23 2004

Keywords

Comments

Lower prime of a difference of 24 between consecutive primes.
23 successive numbers after prime number p are composite. - Artur Jasinski, Jan 15 2007

Crossrefs

Programs

  • Mathematica
    a = {}; Do[If[Prime[x + 1] - Prime[x] == 24, AppendTo[a, Prime[x]]], {x, 1, 10000}]; a (* Artur Jasinski, Jan 15 2007 *)

Extensions

Entry revised by N. J. A. Sloane, Feb 13 2007

A126784 Primes p such that q-p = 32, where q is the next prime after p.

Original entry on oeis.org

5591, 10799, 27701, 27851, 33647, 39047, 41081, 41687, 43721, 44417, 45989, 47459, 50789, 52457, 55259, 55547, 61781, 62351, 64817, 66239, 67307, 69959, 73907, 79907, 80567, 82307, 84089, 88037, 94169, 94961, 99191, 99929, 100559, 102611
Offset: 1

Views

Author

Douglas Winston (douglas.winston(AT)srupc.com), Feb 24 2007

Keywords

Comments

Lower prime of a difference of 32 between consecutive primes.

Crossrefs

Programs

  • PARI
    lista(nn) = {p = 2; while (p < nn, q = nextprime(p+1); if (q - p == 32, print1(p, ", ")); p = q;);} \\ Michel Marcus, Jul 17 2013

A204672 Primes followed by a gap of 120.

Original entry on oeis.org

1895359, 2898239, 6085441, 7160227, 7784039, 7803491, 7826899, 8367397, 8648557, 9452959, 10052071, 10863973, 11630503, 11962823, 12109697, 12230233, 12415681, 14411737, 14531899, 15014557, 15020737, 15611909, 16179041
Offset: 1

Views

Author

M. F. Hasler, Jan 18 2012

Keywords

Crossrefs

Cf. A058193 (first gap of 6n), A140791 (first gap of 10n).
Cf. A126771 (gap 60), A126724 (gap 150), A204673 (gap 180).

Programs

  • MATLAB
    N = 2*10^7; % to get all terms <= N
    P = primes(N+120);
    J = find(P(2:end) - P(1:end-1) == 120);
    P(J)  % Robert Israel, Feb 28 2017
  • Mathematica
    Transpose[Select[Partition[Prime[Range[1100000]],2,1],Last[#]-First[#] == 120&]] [[1]] (* Harvey P. Dale, Jul 11 2014 *)
  • PARI
    g=120;c=o=0;forprime(p=1,default(primelimit),(-o+o=p)==g&write("c:/temp/b204672.txt",c++" "p-g))
    

A098976 Upper prime of a difference of 22 between consecutive primes.

Original entry on oeis.org

1151, 1973, 2333, 2579, 3251, 3491, 3761, 3989, 4049, 5471, 6449, 7151, 8039, 9371, 9461, 9719, 10061, 10133, 10391, 10589, 11351, 11549, 12071, 12323, 13751, 13829, 14243, 14369, 15053, 15959, 17159, 17231, 17783, 18119, 19001, 19841, 19889
Offset: 1

Views

Author

Douglas Winston (douglas.winston(AT)srupc.com), Oct 24 2004

Keywords

Crossrefs

Cf. A031939.

Programs

  • Mathematica
    Select[Partition[Prime[Range[2500]],2,1],#[[2]]-#[[1]]==22&][[All,2]] (* Harvey P. Dale, Oct 14 2018 *)

Formula

a(n) = A061779(n)+22.

A174350 Square array: row n >= 1 lists the primes p for which the next prime is p+2n; read by antidiagonals.

Original entry on oeis.org

3, 5, 7, 11, 13, 23, 17, 19, 31, 89, 29, 37, 47, 359, 139, 41, 43, 53, 389, 181, 199, 59, 67, 61, 401, 241, 211, 113, 71, 79, 73, 449, 283, 467, 293, 1831, 101, 97, 83, 479, 337, 509, 317, 1933, 523, 107, 103, 131, 491, 409, 619, 773, 2113, 1069, 887
Offset: 1

Views

Author

Clark Kimberling, Mar 16 2010

Keywords

Comments

Every odd prime p = prime(i), i > 1, occurs in this array, in row (prime(i+1) - prime(i))/2. Polignac's conjecture states that each row contains an infinite number of indices. In case this does not hold, we can use the convention to continue finite rows with 0's, to ensure the sequence is well defined. - M. F. Hasler, Oct 19 2018
A permutation of the odd primes (A065091). - Robert G. Wilson v, Sep 13 2022

Examples

			Upper left hand corner of the array:
     3     5    11    17    29    41    59    71   101 ...
     7    13    19    37    43    67    79    97   103 ...
    23    31    47    53    61    73    83   131   151 ...
    89   359   389   401   449   479   491   683   701 ...
   139   181   241   283   337   409   421   547   577 ...
   199   211   467   509   619   661   797   997  1201 ...
   113   293   317   773   839   863   953  1409  1583 ...
  1831  1933  2113  2221  2251  2593  2803  3121  3373 ...
   523  1069  1259  1381  1759  1913  2161  2503  2861 ...
  (...)
Row 1: p(2) = 3, p(3) = 5, p(5) = 11, p(7) = 17,... these being the primes for which the next prime is 2 greater: (lesser of) twin primes A001359.
Row 2: p(4) = 7, p(6) = 13, p(8) = 19,... these being the primes for which the next prime is 4 greater: (lesser of) cousin primes A029710.
		

Crossrefs

Rows 35, 40, 45, 50, ...: A204792, A126722, A204764, A050434 (row 50), A204801, A204672, A204802, A204803, A126724 (row 75), A184984, A204805, A204673, A204806, A204807 (row 100); A224472 (row 150).
Column 1: A000230.
Column 2: A046789.

Programs

  • Mathematica
    rows = 10; t2 = {}; Do[t = {}; p = Prime[2]; While[Length[t] < rows - off + 1, nextP = NextPrime[p]; If[nextP - p == 2*off, AppendTo[t, p]]; p = nextP]; AppendTo[t2, t], {off, rows}]; Table[t2[[b, a - b + 1]], {a, rows}, {b, a}] (* T. D. Noe, Feb 11 2014 *)
    t[r_, 0] = 2; t[r_, c_] := Block[{p = NextPrime@ t[r, c - 1], q}, q = NextPrime@ p; While[ p + 2r != q, p = q; q = NextPrime@ q]; p]; Table[ t[r - c + 1, c], {r, 10}, {c, r, 1, -1}] (* Robert G. Wilson v, Nov 06 2020 *)
  • PARI
    A174350_row(g, N=50, i=0, p=prime(i+1), L=[])={g*=2; forprime(q=1+p, , i++; if(p+g==p=q, L=concat(L, q-g); N--||return(L)))} \\ Returns the first N terms of row g. - M. F. Hasler, Oct 19 2018

Formula

a(n) = A000040(A174349(n)). - Michel Marcus, Mar 30 2016

Extensions

Definition corrected and other edits by M. F. Hasler, Oct 19 2018

A224472 Primes followed by a gap of 300.

Original entry on oeis.org

4758958741, 5612345261, 6169169561, 6306815239, 6646984159, 7335508261, 8645089003, 8806019249, 9047808247, 9148138313, 9466071347, 9907846261, 10055451683, 11063821453, 11475026363, 11603081459, 12292390637, 12750876857, 13833827471, 14636472007, 15876700949
Offset: 1

Views

Author

Zak Seidov, Apr 07 2013

Keywords

Comments

The first twin gap equal to 300 occurs for p = 6537587646371. - Giovanni Resta, Apr 07 2013

Crossrefs

Cf. A058193 (first gap of 6n), A140791 (first gap of 10n), A126771 (gap 60), A126724 (gap 150), A204673 (gap 180), A204807 (gap 200), A000230, A001359, A204672, A029710, A031924-A031938, A061779, A098974, A124594-A124596, A126784, A134116-A134124, A204665-A204670.

A126720 Primes p such that p - q = 24, where q is the previous prime before p; or prime numbers preceded by precisely 23 composite numbers.

Original entry on oeis.org

1693, 2203, 4201, 4547, 4783, 5261, 6197, 6421, 6761, 7103, 7393, 7817, 8147, 8353, 9091, 11027, 11657, 11863, 12097, 12143, 13033, 13291, 16057, 16217, 16477, 16787, 16811, 17077, 17707, 18013, 18617, 18661, 19207, 19531, 20507, 22433, 22901
Offset: 1

Views

Author

Artur Jasinski, Feb 13 2007

Keywords

Crossrefs

Programs

  • Mathematica
    a = {}; Do[If[Prime[x + 1] - Prime[x] == 24, AppendTo[a, Prime[x + 1]]], {x, 1, 10000}]; a
  • PARI
    q=2; forprime(p=3,1e5, if(p-q==24, print1(p", ")); q=p) \\ Charles R Greathouse IV, Mar 13 2020

Formula

a(n) = A098974(n) + 24. - Amiram Eldar, Mar 13 2020
a(n) >> n log^2 n. - Charles R Greathouse IV, Mar 13 2020

A320709 Indices of primes followed by a gap (distance to next larger prime) of 22.

Original entry on oeis.org

189, 297, 344, 375, 457, 487, 522, 549, 557, 721, 836, 914, 1010, 1158, 1170, 1197, 1233, 1242, 1272, 1290, 1370, 1390, 1444, 1471, 1625, 1633, 1672, 1683, 1757, 1858, 1975, 1983, 2039, 2074, 2158, 2243, 2248, 2250, 2327, 2370, 2388, 2614, 2638, 2703, 2725, 2838, 2842, 2872
Offset: 1

Views

Author

M. F. Hasler, Oct 19 2018

Keywords

Comments

Indices of the primes listed in A061779.

Crossrefs

Equals A000720 o A061779.
Row 11 of A174349.
Indices of 22's in A001223.
Cf. A029707, A029709, A320701, A320702, ..., A320720 (analog for gaps 2, 4, 6, 8, ..., 44), A116493 (gap 70), A116496 (gap 100), A116497 (gap 200), A116495 (gap 210).

Programs

  • Magma
    [n: n in [1..3000] | NthPrime(n+1) - NthPrime(n) eq 22]; // Vincenzo Librandi, Mar 22 2019
  • Mathematica
    Select[Range[3000], Prime[#] + 22 == Prime[# + 1] &] (* Vincenzo Librandi, Mar 22 2019 *)
  • PARI
    A(N=100,g=22,p=2,i=primepi(p)-1,L=List())={forprime(q=1+p,,i++; if(p+g==p=q, listput(L,i); N--||break));Vec(L)} \\ returns the list of first N terms of the sequence
    

Formula

a(n) = A000720(A061779(n)).
A320709 = { i > 0 | prime(i+1) = prime(i) + 22 }.

A074879 10 - Mod(prime(n),10) when prime(n) + 22 = prime(n+1).

Original entry on oeis.org

1, 9, 9, 3, 1, 1, 1, 3, 3, 1, 3, 1, 3, 1, 1, 3, 1, 9, 1, 3, 1, 3, 1, 9, 1, 3, 9, 3, 9, 3, 3, 1, 9, 3, 1, 1, 3, 9, 9, 3, 3, 1, 1, 3, 9, 9, 1, 1, 3, 3, 1, 3, 3, 1, 1, 1, 9, 9, 1, 1, 9, 3, 1, 9, 1, 3, 1, 1, 9, 1, 1, 1, 3, 1, 3, 9, 9, 1, 1, 1, 1, 1, 3, 1, 1, 1, 3, 1, 9, 9, 1, 3, 9, 1, 3, 1, 9, 3, 1, 9, 9, 9, 1, 1, 1
Offset: 1

Views

Author

Roger L. Bagula, Sep 30 2002

Keywords

Crossrefs

Programs

  • Magma
    [10-(n mod 10): n in PrimesUpTo(50000) | n+22 eq NextPrime(n)];  // Bruno Berselli, Apr 12 2011
  • Mathematica
    10 - Mod[ Prime[ Select[ Range[5220], Prime[ # ] + 22 == Prime[ # + 1] & ]], 10]
    10-Mod[#,10]&/@Transpose[Select[Partition[Prime[Range[6000]],2,1], Last[#]- First[#]==22&]][[1]] (* Harvey P. Dale, Apr 12 2011 *)

Extensions

Edited by Robert G. Wilson v and N. J. A. Sloane, Oct 03 2002
Showing 1-9 of 9 results.