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 1-2 of 2 results.

A269520 Primes 8k + 7 preceding the maximal gaps in A269519.

Original entry on oeis.org

7, 47, 271, 311, 503, 6367, 37223, 42487, 66463, 183527, 259271, 307919, 471007, 1070567, 1801223, 5903687, 6885743, 16936247, 22413319, 38820263, 63977327, 84164447, 147452759, 150334567, 239422639, 300412031, 387154951, 473153959, 539526191, 760400783, 788128039
Offset: 1

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Author

Alexei Kourbatov, Feb 28 2016

Keywords

Comments

Subsequence of A007522.
A269519 lists the corresponding record gap sizes. See more comments there.

Examples

			The first two primes of the form 8k + 7 are 7 and 23, so a(1)=7. The next primes of this form are 31, 47; the gaps 31-23 and 47-31 are not records so nothing is added to the sequence. The next prime of this form is 71 and the gap 71-47=24 is a new record, so a(2)=47.
		

Crossrefs

Programs

  • PARI
    re=0; s=7; forprime(p=23, 1e8, if(p%8!=7, next); g=p-s; if(g>re, re=g; print1(s", ")); s=p)

A269521 Primes 8k + 7 at the end of the maximal gaps in A269519.

Original entry on oeis.org

23, 71, 311, 359, 599, 6551, 37423, 42703, 66751, 183823, 259583, 308263, 471391, 1071023, 1801727, 5904247, 6886367, 16936991, 22414079, 38821039, 63978127, 84165271, 147453599, 150335431, 239423519, 300412927, 387155903, 473154943, 539527199, 760401839, 788129191
Offset: 1

Views

Author

Alexei Kourbatov, Feb 28 2016

Keywords

Comments

Subsequence of A007522.
A269519 lists the corresponding record gap sizes. See more comments there.

Examples

			The first two primes of the form 8k + 7 are 7 and 23, so a(1)=23. The next primes of this form are 31, 47; the gaps 31-23 and 47-31 are not records so nothing is added to the sequence. The next prime of this form is 71 and the gap 71-47=24 is a new record, so a(2)=71.
		

Crossrefs

Programs

  • PARI
    re=0; s=7; forprime(p=23, 1e8, if(p%8!=7, next); g=p-s; if(g>re, re=g; print1(p", ")); s=p)
Showing 1-2 of 2 results.