A179484 - OEIS

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A179484

Primes p such that p+-180 are squares.

181, 349, 2029, 8101

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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 2d=(s+t)(s-t) has a finite set of solutions -- found by scanning the divisors of 2d (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 - Zak Seidov and R. J. Mathar, Jul 19 2010

STATUS

approved