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.

A153406 Smallest of 3 consecutive prime numbers such that p1*p2*p3+d1+d2+1=average of twin prime pairs, d1(delta)=p2-p1,d2(delta)=p3-p2.

Original entry on oeis.org

4813, 9007, 13831, 33791, 35023, 48337, 51577, 52153, 61297, 62207, 77743, 95107, 102607, 105137, 105673, 109663, 111767, 114781, 119747, 128221, 135367, 136727, 138679, 149197, 153949, 159787, 163199, 165437, 174829, 188677, 195973, 208009
Offset: 1

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Comments

4813*4817*4831+4+14=112002971670+-1=primes,...

Crossrefs

Programs

  • Mathematica
    lst={};Do[p1=Prime[n];p2=Prime[n+1];p3=Prime[n+2];d1=p2-p1;d2=p3-p2;a=p1*p2*p3+d1+d2+1;If[PrimeQ[a-1]&&PrimeQ[a+1],AppendTo[lst,p1]],{n,8!}];lst
    s3cpnQ[n_]:=Module[{c=Times@@n+Total[Differences[n]]+1},AllTrue[c+{1,-1}, PrimeQ]]; Transpose[Select[Partition[ Prime[Range[ 20000]],3,1], s3cpnQ]] [[1]] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Nov 05 2014 *)

A153407 Middle of 3 consecutive prime numbers such that p1*p2*p3+d1+d2+1=average of twin prime pairs, d1(delta)=p2-p1,d2(delta)=p3-p2.

Original entry on oeis.org

4817, 9011, 13841, 33797, 35027, 48341, 51581, 52163, 61331, 62213, 77747, 95111, 102611, 105143, 105683, 109673, 111773, 114797, 119759, 128237, 135389, 136733, 138683, 149213, 153953, 159791, 163211, 165443, 174851, 188681, 195977, 208037
Offset: 1

Views

Author

Keywords

Comments

4813*4817*4831+4+14=112002971670+-1=primes,...

Crossrefs

Programs

  • Mathematica
    lst={};Do[p1=Prime[n];p2=Prime[n+1];p3=Prime[n+2];d1=p2-p1;d2=p3-p2;a=p1*p2*p3+d1+d2+1;If[PrimeQ[a-1]&&PrimeQ[a+1],AppendTo[lst,p2]],{n,8!}];lst
    cnpQ[{a_,b_,c_}]:=Module[{p=a*b*c+(b-a)+(c-b)+1},And@@PrimeQ[p+{1,-1}]]; Transpose[Select[Partition[Prime[Range[20000]],3,1],cpnQ]][[2]] (* Harvey P. Dale, Jul 30 2013 *)

A153408 Largest of 3 consecutive prime numbers such that p1*p2*p3 + d1 + d2 + 1 = average of twin prime pairs, d1 (delta) = p2 - p1, d2 (delta) = p3 - p2.

Original entry on oeis.org

4831, 9013, 13859, 33809, 35051, 48353, 51593, 52177, 61333, 62219, 77761, 95131, 102643, 105167, 105691, 109717, 111779, 114799, 119771, 128239, 135391, 136739, 138727, 149239, 153991, 159793, 163223, 165449, 174859, 188687, 195991, 208049
Offset: 1

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Author

Keywords

Examples

			4813*4817*4831 + 4 + 14 = 112002971670 and 112002971670 +- 1 are primes.
		

Crossrefs

Programs

  • Magma
    [NthPrime(k+2):k in [1..20000]| IsPrime(q-1) and IsPrime(q+1) where q is NthPrime(k)* NthPrime(k+1)* NthPrime(k+2)+ NthPrime(k+2)- NthPrime(k)+1]; // Marius A. Burtea, Dec 22 2019
  • Mathematica
    lst={};Do[p1=Prime[n];p2=Prime[n+1];p3=Prime[n+2];d1=p2-p1;d2=p3-p2;a=p1*p2*p3+d1+d2+1;If[PrimeQ[a-1]&&PrimeQ[a+1],AppendTo[lst,p3]],{n,8!}];lst
    Select[Partition[Prime[Range[20000]],3,1],AllTrue[Times@@#+Total[ Differences[ #]]+ {2,0},PrimeQ]&][[All,3]] (* Harvey P. Dale, Apr 22 2022 *)

Extensions

Definition modified by Harvey P. Dale, Apr 22 2022
Showing 1-3 of 3 results.