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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..42.

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: A119066 A019996 A119070 * A073215 A111035 A249277

Adjacent sequences:  A181280 A181281 A181282 * A181284 A181285 A181286

KEYWORD

nonn

AUTHOR

Zak Seidov, Oct 12 2010

STATUS

approved

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Last modified August 14 01:55 EDT 2020. Contains 336476 sequences. (Running on oeis4.)