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A141755 Product of two primes whose sum is a perfect square. 2
4, 14, 39, 46, 55, 94, 155, 158, 183, 203, 291, 295, 299, 323, 334, 446, 579, 583, 695, 718, 799, 878, 943, 955, 959, 979, 1191, 1255, 1411, 1454, 1678, 1703, 2019, 2059, 2159, 2174, 2219, 2395, 2419, 2446, 2491, 2734, 2855, 3043, 3063, 3443, 3459, 3503, 3694 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

MATHEMATICA

Take[ Sort[ Times @@@ Select[ Subsets[ Array[ Prime, 290], {2}], IntegerQ[ Sqrt[ #[[2]] + #[[1]]]] &]], 48]

nn=4000; fQ[n_] := Module[{p, e}, If[n < 2, False, {p, e} = Transpose[FactorInteger[n]]; If[Total[e] != 2, False, IntegerQ[Sqrt[Total[p*e]]]]]]; Select[Range[nn], fQ] (* T. D. Noe, Mar 22 2012 *)

PROG

(Haskell)

a141755 n = a141755_list !! (n-1)

a141755_list = filter f a001358_list where

   f x = a010052' (spf + x `div` spf) == 1 where spf = a020639 x

-- Reinhard Zumkeller, Apr 06 2015

CROSSREFS

Cf. A000040, A000290, A143416.

Cf. A001358, A020639, A010052.

Sequence in context: A111583 A124615 A114845 * A064463 A130423 A266423

Adjacent sequences:  A141752 A141753 A141754 * A141756 A141757 A141758

KEYWORD

nonn

AUTHOR

David Spector (spectord(AT)ccsu.edu) and Robert G. Wilson v, Aug 31 2008

STATUS

approved

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Last modified April 29 19:06 EDT 2017. Contains 285613 sequences.