%I #9 Jul 20 2016 02:07:54
%S 1,3,7,169,677,1355,2711,4304496906163,1852869361516769972676380161,
%T 66703297014603719016349685797,400219782087622314098098114783,
%U 31217143002834540499651652953075,307176687147891878516572265058259
%N a(1) = 1, a(2) = 3 and thereafter a(n) is the smallest number congruent to 1 mod a(n-1) and having the prime signature of n.
%e a(4) = 169 = 13^2 has a prime signature of 4 = 2^2 and 169 == 1 (mod 7 = a(3)).
%K nonn
%O 1,2
%A _Amarnath Murthy_, Jan 05 2006
%E Corrected and extended by _Joshua Zucker_, May 07 2006