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.

A286313 Union of A078561 and A078562.

Original entry on oeis.org

19, 31, 43, 61, 73, 79, 127, 157, 163, 229, 271, 349, 373, 379, 433, 439, 499, 607, 643, 673, 733, 751, 937, 967, 1009, 1093, 1213, 1279, 1291, 1429, 1489, 1543, 1549, 1597, 1609, 1657, 1777, 1861, 1987, 2131, 2203, 2287, 2341, 2347, 2371, 2383, 2389
Offset: 1

Views

Author

Zak Seidov, May 06 2017

Keywords

Comments

Number of terms among first 10^k primes, k=1..8:
0, 1, 17, 105, 646, 4385, 31721, 240346, 1884832.
E.g., k=1, first 10 primes are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, and only 19 is a term of the sequence. - Zak Seidov, May 08 2017
Primes p such that prime(p+2) = p + 10. - Harvey P. Dale, Jan 13 2022

Crossrefs

Cf. A078561 and A078562.

Programs

  • Maple
    select(p -> isprime(p) and isprime(p+10) and (isprime(p+4) xor isprime(p+6)), [seq(i,i=5..10000,2)]); # Robert Israel, May 08 2017
  • Mathematica
    Select[Prime[Range[1000]], NextPrime[#, 2] == # + 10 &]
    Select[Partition[Prime[Range[400]],3,1],#[[1]]+10==#[[3]]&][[All,1]] (* Harvey P. Dale, Jan 13 2022 *)

A078855 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=[6, 4,2]; short d-string notation of pattern = [642].

Original entry on oeis.org

31, 61, 271, 607, 1291, 1657, 1777, 1861, 1987, 2131, 2371, 2677, 2791, 4507, 5407, 5431, 5641, 7867, 9001, 11821, 13681, 14551, 17377, 18121, 18301, 20347, 21481, 22147, 24097, 27271, 32707, 35521, 36781, 37561, 41221, 41947, 42397, 42451
Offset: 1

Views

Author

Labos Elemer, Dec 11 2002

Keywords

Comments

Subsequence of A078562. - R. J. Mathar, May 06 2017

Examples

			p=31,31+6=37,31+6+4=41,31+6+4+2=43 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
    Transpose[Select[Partition[Prime[Range[4500]],4,1],Differences[#] == {6,4,2}&]][[1]] (* Harvey P. Dale, Feb 10 2015 *)

Formula

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

Extensions

Listed terms verified by Ray Chandler, Apr 20 2009

A078856 Initial term in sequence of four consecutive primes whose consecutive differences have d-pattern = [6, 4, 6]; short d-string notation for pattern = [646].

Original entry on oeis.org

73, 157, 373, 433, 1543, 2341, 2383, 3313, 3607, 4441, 4993, 5851, 6037, 6961, 7237, 8731, 9613, 9733, 10723, 13093, 14143, 14731, 16411, 16921, 17971, 18787, 20107, 21391, 23011, 23593, 25111, 25237, 25447, 27793, 30103, 30697, 32353, 32563
Offset: 1

Views

Author

Labos Elemer, Dec 11 2002

Keywords

Examples

			p=73, 73 + 6 = 79, 73 + 6 + 4 = 83, 73 + 6 + 4 + 6 = 89 are consecutive primes.
		

Crossrefs

Subsequence of A078562.
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

  • Maple
    N:=10^4: # to get all terms <= N.
    Primes:=select(isprime,[seq(i,i=3..N+16,2)]):
    Primes[select(t->[Primes[t+1]-Primes[t], Primes[t+2]-Primes[t+1],
    Primes[t+3]-Primes[t+2]]=[6,4,6], [$1..nops(Primes)-3])]; # Muniru A Asiru, Aug 04 2017
  • Mathematica
    Transpose[Select[Partition[Prime[Range[10000]],4,1],Differences[#]=={6,4,6}&]][[1]] (* Harvey P. Dale, Apr 22 2014 *)

Formula

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

Extensions

Listed terms verified by Ray Chandler, Apr 20 2009
Name simplified by Michel Marcus, Aug 11 2017

A078561 p, p+4 and p+10 are consecutive primes.

Original entry on oeis.org

19, 43, 79, 127, 163, 229, 349, 379, 439, 499, 643, 673, 937, 967, 1009, 1093, 1213, 1279, 1429, 1489, 1549, 1597, 1609, 2203, 2347, 2389, 2437, 2539, 2689, 2833, 2953, 3079, 3319, 3529, 3613, 3793, 3907, 3919, 4003, 4129, 4447, 4639, 4789, 4933, 4999
Offset: 1

Views

Author

Labos Elemer, Dec 10 2002

Keywords

Comments

Subsequence of A029710. - R. J. Mathar, May 06 2017

Examples

			Between p and p+10 [46] difference-pattern: 19(4)23(6)29;
		

Crossrefs

Cf. analogous inter-prime d-patterns with d<=6: A022004[24], A022005[42], A049437[26], A049438[62], A078561[46], A078562[64], A047948[66].

Programs

  • Mathematica
    Select[Prime@ Range[10^3], Differences@ NestList[NextPrime, #, 2] == {4, 6} &] (* Michael De Vlieger, May 06 2017 *)
    Select[Partition[Prime[Range[700]],3,1],Differences[#]=={4,6}&][[All,1]] (* Harvey P. Dale, Mar 24 2018 *)
  • PARI
    isok(p) = isprime(p) && (nextprime(p+1) == p+4) && (nextprime(p+5) == p+10); \\ Michel Marcus, Dec 20 2013
    
  • PARI
    is(n)=isprime(n) && isprime(n+4) && isprime(n+10) && !isprime(n+6) && n>3 \\ Charles R Greathouse IV, Dec 20 2013
Showing 1-4 of 4 results.