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 1-3 of 3 results.

A054678 n consecutive primes differ by a multiple of 4 starting at a(n).

Original entry on oeis.org

7, 89, 199, 463, 463, 463, 11593, 11593, 183091, 241603, 241603, 241603, 9177431, 9177431, 12270077, 105639091, 297779117, 297779117, 727334879, 1113443017, 1113443017, 1113443017, 1113443017, 79263248027, 84676452781, 113391385603
Offset: 2

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Author

Jeff Burch, Apr 18 2000

Keywords

Crossrefs

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Nov 09 2000
More terms from Jens Kruse Andersen, May 29 2006

A054679 First of n consecutive primes which differ by a multiple of 6.

Original entry on oeis.org

2, 23, 47, 251, 1741, 1741, 19471, 118801, 148531, 148531, 406951, 1820111, 2339041, 19725473, 19725473, 73451737, 232301497, 400414121, 489144599, 489144599, 766319189, 766319189, 21549657539, 21549657539, 21549657539, 140432294381, 140432294381, 437339303279, 1552841185921, 1552841185921, 1552841185921
Offset: 1

Views

Author

Jeff Burch, Apr 18 2000

Keywords

Comments

See A276414 for the indices of these primes. - M. F. Hasler, Sep 02 2016
The sequence is infinite, by Shiu's theorem. - Jonathan Sondow, Jun 22 2017

Crossrefs

Formula

a(n) = A000040(A276414(n)). - M. F. Hasler, Sep 02 2016
a(n) = min(A057620(n), A057621(n)) for all n >= 1. - M. F. Hasler, Sep 03 2016

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Nov 09 2000
More terms from Jens Kruse Andersen, May 30 2006
Initial term and a(27)-a(31) added and name edited by M. F. Hasler, Sep 02 2016

A259360 Initial prime in the least set of exactly n+1 consecutive primes with n gaps all multiples of 4.

Original entry on oeis.org

7, 89, 199, 883, 12401, 463, 36551, 11593, 183091, 766261, 3358169, 241603, 11739307, 9177431, 12270077, 105639091, 310523021, 297779117, 727334879, 5344989829, 1481666377, 2572421893, 1113443017, 79263248027, 84676452781
Offset: 1

Views

Author

Zak Seidov, Jun 24 2015

Keywords

Examples

			a(6)=463 because the first set of 7 consecutive primes is {463,467,479,487,491,499,503} with 6 gaps {4,12,8,4,8,4} all multiples of 4 while the next prime after 503 is 509 and 509-503=6 is not a multiple of 4.
		

Crossrefs

Programs

  • PARI
    back(p,n)=while(n,p=precprime(p-1); n--); p
    v=vector(20); g=0; p=2; forprime(q=3,1e6, if((q-p)%4, if(g&&g<=#v&&v[g]==0, v[g]=back(p,g)); g=0, g++);p=q); v \\ Charles R Greathouse IV, Jul 14 2015

Extensions

a(13)-a(14) corrected by Charles R Greathouse IV, Jul 14 2015
a(24)-a(25) by Zak Seidov, Jul 15 2015
Showing 1-3 of 3 results.