A179484 Primes p such that p+-180 are squares.

181, 349, 2029, 8101

Offset

1,1

Comments

Sequences of this type searching for p+d=s^2, p-d=t^2 (here: d=180) are finite because the difference 2*d=(s+t)*(s-t) has a finite set of solutions -- found by scanning the divisors of 2*d (see A060829, A061409). - R. J. Mathar, Jul 20 2010

Links

Table of n, a(n) for n=1..4.

Example

181-180=1^2, 181+180=19^2.
349-180=13^2, 349+180=23^2.
2029-180=43^2, 2029+180=47^2.
8101-180=89^2, 8101+180=91^2.

Mathematica

q=180; Select[Table[Prime[n], {n, 3*9!}], IntegerQ[Sqrt[ #-q]]&&IntegerQ[Sqrt[ #+q]]&]

Crossrefs

Sequence in context: A142920 A142058 A138397 * A142258 A323192 A142030

Adjacent sequences: A179481 A179482 A179483 * A179485 A179486 A179487

Keyword

nonn,fini,full

Author

Vladimir Joseph Stephan Orlovsky, Jul 16 2010

Extensions

keyword:fini,full inserted by Zak Seidov and R. J. Mathar, Jul 19 2010

Status

approved