%I A108278
%S A108278 12,30,42,60,102,108,198,312,462,522,600,810,828,1020,1050,1062,1278,
%T A108278 1452,1488,1872,1950,2028,2130,2142,2340,2790,2802,2970,3000,3120,3252,
%U A108278 3300,3330,3672,3930,4020,4092,4230,4548,4800,5280,5640,5652,5658,6198
%N A108278 Numbers n such that n^2-1 and n^2+1 are semiprimes.
%e A108278 a(1)=12 because 12^2-1=143=11*13 and 12^2+1=145=5*29 are both semiprimes.
%Y A108278 Cf. A001358 semiprimes, A069062 n^2-1 and n^2+1 have the same number 
               of divisors.
%Y A108278 Sequence in context: A024364 A093507 A145470 this_sequence A135502 A125582 
               A031107
%Y A108278 Adjacent sequences: A108275 A108276 A108277 this_sequence A108279 A108280 
               A108281
%K A108278 nonn
%O A108278 1,1
%A A108278 Hugo Pfoertner (hugo(AT)pfoertner.org), May 30 2005