A203815 - OEIS

%I #13 Mar 31 2012 10:32:52

%S 14449,4651249,14592449,25281961,64516961,144552049,4963984001,

%T 10241442401,121828921681,1089936421201,1589776384961,4640334443681,

%U 19713620187049,25593280441009,81105458016049,121521961692601,445309309225961

%N Primes which are the decimal concatenation of two squares in more than one way.

%C Subsequence of A167535.

%e a(1) = 14449 = the concatenation of 12^2 and 7^2 and of 38^2 and 3^2.

%e a(5) = 64516961 = the concatenation of 8^2 and 719^2 and of 254^2 and 31^2.

%t K[m_Integer, n_Integer] := n+m*10^IntegerLength[n]; k=-1; V={}; g=5000000; W={}; While[k<g, k++; m=2 k+1; n=0; While[n<2 g, n++; a=K[n^2, m^2]; If[a>10 (2 g)^2, n=2 g, If[PrimeQ[a], V={V, a}]]]]; V=Flatten[V]; W1=Sort[V]; W2=Union[V](*= A167535*); i=0; While[i<Length[W1]-1, i++; If[W1[[i+1]]==W1[[i]], W=Append[W, W1[[i]]]]]; Union[W]

%Y Cf. A167535.

%K nonn,base

%O 1,1

%A _Emmanuel Vantieghem_, Jan 06 2012