%I #5 Jul 01 2019 23:10:11
%S 18,19,23,27,28,29,33,34,39,40,46,47,53,60,61,77,102,109,119,125,129,
%T 131,147,154,159,160,161,167,173,175,177,185,186,187,189,190,192,193,
%U 194,200,207,219,237,287,293,297,299,303,327,333,334,340,345,346,351,359,365,371,373,383,384,390,391,397,398
%N Positions of 3's on the spiral defined in A308890.
%C Add 1 to the terms of A308888.
%Y Cf. A308884-A308895.
%K nonn
%O 1,1
%A _N. J. A. Sloane_, Jul 01 2019