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.

A236461 Sum of two consecutive primes that is also sum of two consecutive even positive squares.

Original entry on oeis.org

52, 100, 340, 1460, 2452, 2740, 4420, 20404, 21220, 36452, 48052, 62660, 66980, 94180, 103060, 108580, 128020, 140452, 142580, 169364, 171700, 195940, 221780, 254900, 260644, 361252, 378452, 490052, 498004, 717604, 736900, 756452, 766324, 791284, 879140, 889780, 916660, 1016740, 1104100, 1164340, 1232452, 1283204
Offset: 1

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Author

Zak Seidov, Jan 26 2014

Keywords

Comments

All values of (q - p) are multiples of 6.
m = p + q = x^2 + (x+2)^2; {m,p,q,x}: {52, 23, 29, 4}, {100, 47, 53, 6}, {340, 167, 173, 12}, {1460, 727, 733, 26}, {2452, 1223, 1229, 34}, {2740, 1367, 1373, 36}, {4420, 2207, 2213, 46}.
Intersection of A001043 and A108099. - Michel Marcus, Jan 27 2014

Examples

			52 = 23 + 29 = 4^2 + 6^2.
		

Crossrefs

Programs

  • Maple
    count:= 0: R:= NULL:
    for m from 1 while count < 100 do
      y:= 8*m^2+8*m+4;
      if prevprime(y/2) + nextprime(y/2)=y then
         count:= count+1;
         R:= R, y;
      fi
    od:
    R; # Robert Israel, Jan 07 2020
  • Mathematica
    With[{nn=100000},Intersection[Total/@Partition[Prime[Range[nn]],2,1],Total/@ Partition[Range[2,2nn,2]^2,2,1]]] (* Harvey P. Dale, Jul 03 2021 *)
  • PARI
    v=vector(1300000); pp=3; forprime(p=5,#v/2,v[p+pp]++;pp=p);forstep(k=2,sqrtint(#v/2)-1,2,v[2*(k^2+2*k+2)]++);for(k=1,#v,if(v[k]==2,print1(k,", "))) \\ Hugo Pfoertner, Jan 07 2020