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A181283
Numbers n with property that (n+1)*prime(n+1)-n*prime(n) is a perfect square s^2.
0
1, 2, 24, 45, 58, 64, 135, 168, 287, 325, 455, 601, 1506, 1965, 1990, 2070, 2189, 2428, 3967, 4017, 4388, 4895, 6966, 7419, 9252, 10144, 10242, 10618, 12980, 14175, 14385, 14740, 15140, 18724, 22424, 24203, 24935, 24989, 25171, 25974, 27817, 29688
OFFSET
1,2
FORMULA
{n,s}:{1,2},{2,3},{24,17},{45,17},{58,25},{64,21},{135,43},{168,55},{287,55}.
MATHEMATICA
Select[Range[30000], IntegerQ[Sqrt[(#+1)Prime[#+1]-# Prime[#]]]&] (* Harvey P. Dale, Mar 20 2012 *)
PROG
(PARI) a=2; {for(n=1, 10^5, b=nextprime(a+1); issquare((n+1)*b-n*a)&print(n); a=b)}
CROSSREFS
Cf. A175897.
Sequence in context: A368042 A343817 A119070 * A368360 A073215 A111035
KEYWORD
nonn
AUTHOR
Zak Seidov, Oct 12 2010
STATUS
approved