%I #5 Dec 05 2013 19:55:39
%S 1,2,3,6,19,99,307,9379,1726174,13347339102,321699559882750174,
%T 4716070968330003553938242926174,
%U 23987291841663781653328392594255840802707701158676395299
%N Initial terms of groups in A075631.
%F For n>1, a(n) = A075634(n-1) + 1. Also, a(n) = (sqrt(8*(A075631(1) + A075631(2) + ... + A075631(n-1)) + 1) + 1) / 2. [From _Max Alekseyev_, May 08 2009]
%Y Cf. A075631, A075632, A075634.
%K nonn
%O 1,2
%A _Amarnath Murthy_, Sep 30 2002
%E More terms from Jonathan Cross (jcross(AT)juggler.net), May 08 2004
%E One more term from _Max Alekseyev_, May 08 2009