A153048 Numbers n with property that n^2 is a concatenation of two 3-digit primes.

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.

Links

Table of n, a(n) for n=1..15.

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

Adjacent sequences: A153045 A153046 A153047 * A153049 A153050 A153051

Keyword

fini,full,nonn,base

Author

Zak Seidov, Dec 17 2008

Status

approved