A118593 Larger member of twin prime pairs whose sum is a square.

19, 73, 883, 1153, 2593, 3529, 4051, 15139, 20809, 34849, 46819, 69193, 83233, 103969, 112339, 149059, 176419, 180001, 206083, 281251, 362953, 388963, 438049, 472393, 478243, 538723, 649801, 734473, 808993, 960499, 1080451, 1143073

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..180 from Harvey P. Dale)

Formula

a(n) = A069496(n) + 2.

Example

17 and 19 are twin primes whose sum is 36, a square, so 19 is a term in this sequence.

Mathematica

Transpose[Select[Partition[Prime[Range[200000]], 2, 1], #[[2]]-#[[1]]==2 && IntegerQ[Sqrt[Total[#]]]&]][[2]] (* Harvey P. Dale, Jul 29 2014 *)

Prog

(PARI) g(n) = for(x=1, n, p1=prime(x); p2=prime(x+1); if(p2-p1==2&issquare(p1+p2), print1(p2", ")))

Crossrefs

Cf. A069496, A118593.

Sequence in context: A220447 A294460 A373720 * A047979 A373668 A290241

Adjacent sequences: A118590 A118591 A118592 * A118594 A118595 A118596

Keyword

easy,nonn,changed

Author

Cino Hilliard, May 08 2006

Status

approved