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.

Previous Showing 11-16 of 16 results.

A078850 Initial term in sequence of four consecutive primes separated by 3 consecutive differences each <=6 (i.e., when d=2,4 or 6) and forming d-pattern=[4,2,6]; short d-string notation of pattern = [426].

Original entry on oeis.org

67, 1447, 2377, 2707, 5437, 5737, 7207, 9337, 11827, 12037, 19207, 21487, 21517, 23197, 26107, 26947, 28657, 31147, 31177, 35797, 37357, 37567, 42697, 50587, 52177, 65167, 67927, 69997, 71707, 74197, 79147, 81547, 103087, 103387, 106657
Offset: 1

Views

Author

Labos Elemer, Dec 11 2002

Keywords

Comments

Subsequence of A022005. - R. J. Mathar, May 06 2017

Examples

			p=67,67+4=71,67+4+2=73,67+4+2+6=79 are consecutive primes.
		

Crossrefs

Cf. analogous prime quadruple sequences with various possible {2, 4, 6}-difference-patterns in brackets: A007530[242], A078847[246], A078848[264], A078849[266], A052378[424], A078850[426], A078851[462], A078852[466], A078853[624], A078854[626], A078855[642], A078856[646], A078857[662], A078858[664], A033451[666].

Programs

  • Mathematica
    d = {4, 2, 6}; First /@ Select[Partition[Prime@ Range@ 12000, Length@ d + 1, 1], Differences@ # == d &] (* Michael De Vlieger, May 02 2016 *)

Formula

Primes p = p(i) such that p(i+1)=p+4, p(i+2)=p+4+2, p(i+3)=p+4+2+6.

Extensions

Listed terms verified by Ray Chandler, Apr 20 2009

A079016 Suppose p and q = p+12 are primes. Define the difference pattern of (p,q) to be the successive differences of the primes in the range p to q. There are 14 possible difference patterns, namely [12], [2,10], [4,8], [6,6], [8,4], [10,2], [2,4,6], [2,6,4], [4,2,6], [4,6,2], [6,2,4], [6,4,2], [2,4,2,4] and [4,2,4,2]. Sequence gives smallest value of p for each difference pattern, sorted by magnitude.

Original entry on oeis.org

5, 7, 17, 19, 29, 31, 47, 67, 89, 137, 139, 199, 397, 1601
Offset: 1

Views

Author

Labos Elemer, Jan 24 2003

Keywords

Examples

			p=1601, q=1613 has difference pattern [6,2,4] and {1601,1607,1609,1613} is the corresponding consecutive prime 4-tuple.
		

Crossrefs

A022006(1)=5, A022007(1)=7, A078847(1)=17, A078851(1)=19, A078848(1)=29, A078855(1)=31, A047948(1)=47, A078850(1)=67, A031930(1)=A000230(6)=199, A046137(1)=7, A078853(1)=1601.

Programs

  • Mathematica
    Function[s, Function[t, Union@ Flatten@ Map[s[[First@ Position[t, #]]] &, {{12}, {2, 10}, {4, 8}, {6, 6}, {8, 4}, {10, 2}, {2, 4, 6}, {2, 6, 4}, {4, 2, 6}, {4, 6, 2}, {6, 2, 4}, {6, 4, 2}, {2, 4, 2, 4}, {4, 2, 4, 2}}]]@ Map[Differences@ Select[Range[#, # + 12], PrimeQ] &, s]]@ Select[Prime@ Range[10^3], PrimeQ[# + 12] &] (* Michael De Vlieger, Feb 25 2017 *)

A078961 Primes p such that the differences between the 5 consecutive primes starting with p are (6,4,2,4).

Original entry on oeis.org

31, 1291, 1861, 1987, 2677, 4507, 5641, 7867, 13681, 17377, 24097, 35521, 42451, 44257, 55807, 80671, 88651, 88801, 93481, 110557, 113011, 113161, 118891, 134581, 155371, 163981, 198817, 221707, 234181, 266671, 269377, 284731, 290611, 313981, 331537, 332461, 344161
Offset: 1

Views

Author

Labos Elemer, Dec 19 2002

Keywords

Comments

Equivalently, primes p such that p, p+6, p+10, p+12 and p+16 are consecutive primes.

Examples

			31 is a term since 31, 37 = 31 + 6, 41 = 31 + 10, 43 = 31 + 12 and 47 = 31 + 16 are consecutive primes.
		

Crossrefs

Subsequence of A078855. - R. J. Mathar, May 06 2017

Programs

  • Mathematica
    Transpose[Select[Partition[Prime[Range[26000]],5,1],Differences[#]=={6,4,2,4}&]][[1]] (* Harvey P. Dale, Aug 26 2014 *)
  • PARI
    list(lim) = {my(p1 = 2, p2 = 3, p3 = 5, p4 = 7); forprime(p5 = 11, lim, if(p2 - p1 == 6 && p3 - p2 == 4 && p4 - p3 == 2 && p5 - p4 == 4, print1(p1, ", ")); p1 = p2; p2 = p3; p3 = p4; p4 = p5);} \\ Amiram Eldar, Feb 22 2025

Formula

From Amiram Eldar, Feb 22 2025: (Start)
a(n) == 1 (mod 6).
a(n) == 1 or 7 (mod 30). (End)

Extensions

Edited by Dean Hickerson, Dec 20 2002

A078962 Primes p such that the differences between the 5 consecutive primes starting with p are (6,4,2,6).

Original entry on oeis.org

61, 2371, 5431, 11821, 21481, 37561, 50581, 69991, 124291, 126481, 139291, 223831, 230761, 268771, 272341, 275911, 305401, 363361, 365461, 388471, 498391, 516151, 556261, 561091, 585031, 752281, 776551, 783781, 812341, 832621, 911161, 942031, 950221, 1030021, 1108561
Offset: 1

Views

Author

Labos Elemer, Dec 19 2002

Keywords

Comments

Equivalently, primes p such that p, p+6, p+10, p+12 and p+18 are consecutive primes.

Examples

			61 is in the sequence since 61, 67 = 61 + 6, 71 = 61 + 10, 73 = 61 + 12 and 79 = 61 + 18 are consecutive primes.
		

Crossrefs

Subsequence of A078855. - R. J. Mathar, May 06 2017

Programs

  • Mathematica
    Select[Partition[Prime[Range[50000]], 5, 1], Differences[#] == {6,4,2,6} &][[;;, 1]] (* Amiram Eldar, Feb 22 2025 *)
  • PARI
    list(lim) = {my(p1 = 2, p2 = 3, p3 = 5, p4 = 7); forprime(p5 = 11, lim, if(p2 - p1 == 6 && p3 - p2 == 4 && p4 - p3 == 2 && p5 - p4 == 6, print1(p1, ", ")); p1 = p2; p2 = p3; p3 = p4; p4 = p5);} \\ Amiram Eldar, Feb 22 2025

Formula

a(n) == 1 (mod 30). - Amiram Eldar, Feb 22 2025

Extensions

Edited by Dean Hickerson, Dec 20 2002

A290635 Greatest of 4 consecutive primes with consecutive gaps 6, 4, 2.

Original entry on oeis.org

43, 73, 283, 619, 1303, 1669, 1789, 1873, 1999, 2143, 2383, 2689, 2803, 4519, 5419, 5443, 5653, 7879, 9013, 11833, 13693, 14563, 17389, 18133, 18313, 20359, 21493, 22159, 24109, 27283, 32719, 35533, 36793, 37573, 41233, 41959, 42409, 42463, 44269, 47149, 50593, 55219, 55819, 55933
Offset: 1

Views

Author

Muniru A Asiru, Aug 08 2017

Keywords

Comments

All terms = {13, 19} mod 30.

Examples

			43 is a member of the sequence because 43 is the greatest of the 4 consecutive primes 31, 37, 41, 43 with consecutive gaps 6, 4, 2; that is, 37 - 31 = 6, 41 - 37 = 4, 43 - 41 = 2.
		

Crossrefs

Subsequence of A006512 and A098413.

Programs

  • GAP
    K:=2*10^5+1;; # to get all terms <= K.
    P:=Filtered([1,3..K],IsPrime);;  I:=Reversed([2,4,6]);;
    P1:=List([1..Length(P)-1],i->P[i+1]-P[i]);;
    P2:=List([1..Length(P)-Length(I)],i->[P1[i],P1[i+1],P1[i+2]]);;
    P3:=List(Positions(P2,I),i->P[i+Length(I)]);
    # More efficient
    
  • GAP
    Filtered(Set(Flat(List([13,19],j->List([1..2000],i->30*i+j)))),j->IsPrime(j) and IsPrime(j-12) and not IsPrime(j-10) and not IsPrime(j-8) and IsPrime(j-6) and not IsPrime(j-4) and IsPrime(j-2)); # Muniru A Asiru, Jul 03 2018
    
  • Maple
    for i from 1 to 10^5 do if ithprime(i+1)=ithprime(i)+6 and ithprime(i+2)=ithprime(i)+4 and ithprime(i+3)=ithprime(i)+2  then print(ithprime(i+3)); fi; od; # Corrected by Robert Israel, Jun 28 2018
    # More efficient:
    primes:= select(isprime,[seq(seq(30*i+j,j=[13,19]),i=1..10^4)]):
    select(t -> isprime(t-2) and isprime(t-6) and isprime(t-12) and not isprime(t-8), primes); # Robert Israel, Jun 28 2018
  • Mathematica
    With[{s = Differences@ Prime@ Range[10^4]}, Prime[1 + SequencePosition[s, {6, 4, 2}][[All, -1]] ] ] (* Michael De Vlieger, Aug 16 2017 *)
    Select[Partition[Prime[Range[6000]],4,1],Differences[#]=={6,4,2}&][[All,4]] (* Harvey P. Dale, Feb 13 2022 *)
  • PARI
    is(n) = if(!ispseudoprime(n), return(0), my(v=[n-2, n-6, n-12]); if(v[1]==precprime(n-1) && v[2]==precprime(v[1]-1) && v[3]==precprime(v[2]-1), return(1))); 0 \\ Felix Fröhlich, Aug 10 2017

Formula

a(n) = A078855(n) + 12.

A385035 Primes p such that p + 8, p + 14, p + 18 and p + 20 are also primes.

Original entry on oeis.org

23, 53, 89, 263, 599, 1283, 1979, 3449, 5399, 5639, 11813, 14543, 41213, 42443, 44249, 47129, 55799, 57773, 65699, 74699, 75983, 79613, 84299, 87539, 88643, 88793, 88799, 113153, 115763, 126473, 143813, 148913, 150203, 160073, 163973, 167099, 176489, 178799, 178889, 209249
Offset: 1

Views

Author

Alexander Yutkin, Jun 15 2025

Keywords

Examples

			p=23: 23+8=31, 23+14=37, 23+18=41, 23+20=43 —> prime quintuple: (23, 31, 37, 41, 43).
		

Crossrefs

Cf. A000040.
Cf. A172454 [2, 4, 6], A078855 [6, 4, 2], A187057 [2, 4, 6, 8].

Programs

  • Magma
    [p: p in PrimesUpTo(300000) | IsPrime(p+8) and IsPrime(p+14) and IsPrime(p+18) and IsPrime(p+20)]; // Vincenzo Librandi, Jul 04 2025
  • Maple
    q:= p-> andmap(i-> isprime(p+i), [0, 8, 14, 18, 20]):
    select(q, [5+6*i$i=0..35000])[];  # Alois P. Heinz, Jun 16 2025
  • Mathematica
    Select[Prime[Range[20000]], AllTrue[#+{8, 14, 18,20}, PrimeQ]&] (* Stefano Spezia, Jun 18 2025 *)
Previous Showing 11-16 of 16 results.