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.

A082509 Differences between consecutive primes that are not powers of 2 in order of their appearance. Differences which are powers of 2 are omitted from A001223.

Original entry on oeis.org

6, 6, 6, 6, 6, 6, 6, 14, 6, 10, 6, 6, 6, 6, 10, 12, 12, 6, 10, 6, 6, 6, 6, 10, 14, 14, 6, 10, 6, 6, 6, 6, 10, 10, 6, 6, 12, 6, 12, 18, 6, 10, 6, 6, 6, 10, 6, 6, 6, 6, 12, 10, 6, 6, 12, 6, 10, 10, 6, 6, 6, 14, 10, 12, 10, 10, 14, 14, 20, 10, 6, 6, 14, 6, 6, 6, 12, 6, 10, 6, 10, 10, 6, 18, 6, 6, 6
Offset: 1

Views

Author

Labos Elemer, Apr 28 2003

Keywords

Crossrefs

Programs

  • Mathematica
    Do[s=Log[2, Prime[n+1]-Prime[n]]; If[ !IntegerQ[s], Print[Prime[n+1]]], {n, 1, 1000}]
    Module[{nn=250,twos},twos=2^Range[0,Floor[Log[2,Prime[nn]]]];Select[ Differences[ Prime[Range[nn]]],!MemberQ[twos,#]&]] (* Harvey P. Dale, Apr 18 2012 *)
  • PARI
    list(lim) = {my(p = 2, d); forprime(q = 3, lim, d = q - p; if(d >> valuation(d, 2) > 1, print1(d, ", ")); p = q);} \\ Amiram Eldar, Feb 16 2025

A130796 Primes p such that nextprime(p)-p is not power of 2.

Original entry on oeis.org

23, 31, 47, 53, 61, 73, 83, 113, 131, 139, 151, 157, 167, 173, 181, 199, 211, 233, 241, 251, 257, 263, 271, 283, 293, 317, 331, 337, 353, 367, 373, 383, 409, 421, 433, 443, 467, 503, 509, 523, 541, 547, 557, 563, 571, 577, 587, 593, 601, 607, 619, 631, 647
Offset: 1

Views

Author

Zak Seidov, Aug 20 2007

Keywords

Comments

Indices of primes are 9,11,15,16,18,21,23,30,32,34,36,37,39,40,42,46,47,51, 53,54,55,56,58,61,62,66,... (subsequence of A113339).

Crossrefs

Cf. A001223 Differences between consecutive primes, A082509 Differences between consecutive primes that are not powers of 2, A082508 Differences between consecutive primes that are powers of 2, A113339 Integers n such that prime(n+1)-prime(n) is nonprime, squarefree.

Programs

  • Mathematica
    <Harvey P. Dale, Apr 20 2011 *)

A082510 Differences of consecutive primes being divisible by 6 in order of their appearance in A001223: terms not divisible by 6 are omitted from A001223.

Original entry on oeis.org

6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 12, 12, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 12, 6, 12, 18, 6, 6, 6, 6, 6, 6, 6, 6, 12, 6, 6, 12, 6, 6, 6, 6, 12, 6, 6, 6, 6, 6, 12, 6, 6, 6, 18, 6, 6, 6, 6, 6, 6, 12, 6, 6, 6, 12, 18, 6, 6, 12, 6, 6, 6, 18, 6, 6, 12, 6, 12, 12, 12, 6, 6, 6, 6, 6, 6, 24, 12, 6, 6, 6, 18
Offset: 1

Views

Author

Labos Elemer, Apr 28 2003

Keywords

Crossrefs

Programs

  • Mathematica
    Do[s=Mod[d=Prime[n+1]-Prime[n], 6]; If[Equal[s, 0], Print[d]], {n, 1, 1000}]
    Select[Last[#]-First[#]&/@Partition[Prime[Range[500]],2,1], Divisible[ #,6]&] (* Harvey P. Dale, Mar 18 2012 *)
    Select[Differences[Prime[Range[500]]],Divisible[#,6]&] (* Harvey P. Dale, May 13 2020 *)
Showing 1-3 of 3 results.