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 11-12 of 12 results.

A155187 Prime numbers q of primitive Pythagorean triangles such that perimeters are averages of twin prime pairs, p+1=q(prime), a=q^2-p^2, c=q^2+p^2, b=2*p*q, ar=a*b/2; s=a+b+c, s-+1 are primes.

Original entry on oeis.org

2, 3, 11, 71, 227, 491, 683, 1103, 1187, 2591, 3923, 4271, 4931, 6737, 7193, 7703, 8093, 8753, 8963, 9173, 9377, 10271, 13043, 13451, 13997, 15233, 15443, 15803, 15887, 17957, 18701, 19961, 20681, 21701, 22031, 22073, 24371, 24473, 24683
Offset: 1

Views

Author

Keywords

Comments

p=1, q=2(prime), a=3, b=4, c=5, s=12-+1 primes, ...

Crossrefs

Programs

  • Mathematica
    lst={};Do[p=n;q=p+1;a=q^2-p^2;c=q^2+p^2;b=2*p*q;ar=a*b/2;s=a+b+c;If[PrimeQ[s-1]&&PrimeQ[s+1],If[PrimeQ[q],AppendTo[lst,q]]],{n,8!}];lst

A228978 Primes p such that p and p+2, p^2+p-1 and p^2+p+1, and (p^2+p-1)^2+p^2+p-2 and (p^2+p-1)^2+p^2+p are three pairs of twin primes.

Original entry on oeis.org

11767181, 35057849, 84428051, 91460249, 105929711, 115401719, 162790781, 197352401, 217761851, 235863209, 266250839, 284597741, 370000511, 386278019, 554761451, 576412271, 581549669, 592975109, 611599661, 625806761, 626450411, 655727771, 670280591, 680468669, 744737111, 883687349, 1085880641, 1119813311, 1139369111
Offset: 1

Views

Author

Pierre CAMI, Sep 10 2013

Keywords

Comments

Subsequence of A228968.

Crossrefs

Programs

  • Mathematica
    tptpQ[n_]:=Module[{p2=n^2+n},AllTrue[{p2-1,p2+1,(p2-1)^2+p2-2,(p2-1)^2+ p2},PrimeQ]]; Select[Transpose[Select[Partition[ Prime[ Range[ 58*10^6]],2,1], #[[2]]-#[[1]]==2&]][[1]],tptpQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Nov 10 2014 *)

Extensions

Corrected by Harvey P. Dale, Nov 10 2014
Previous Showing 11-12 of 12 results.