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A153048
Numbers n with property that n^2 is a concatenation of two 3-digit primes.
5
319, 337, 357, 363, 371, 387, 409, 447, 591, 663, 681, 701, 801, 827, 893
OFFSET
1,1
COMMENTS
There are exactly 15 such numbers.
EXAMPLE
Corresponding squares are: 101761, 113569, 127449, 131769, 137641, 149769, 167281, 199809, 349281, 439569, 463761, 491401, 641601, 683929, 797449.
MATHEMATICA
c = 0; t = 1000; re = Sort[Reap[Do[If[PrimeQ[p], Do[If[PrimeQ[q], r = p*t + q; s = Sqrt[r]; If[s == Floor[s], c++; Sow[s]]], {q, 101, 999, 2}]], {p, 101, 999, 2}]][[2, 1]]]
CROSSREFS
Sequence in context: A225579 A261281 A126838 * A053020 A250660 A252410
KEYWORD
fini,full,nonn,base
AUTHOR
Zak Seidov, Dec 17 2008
STATUS
approved