%I M2842 #18 Jul 04 2019 15:47:46
%S 3,10,31,101,311,962,3132,10202,31412,96722,299183,925445,3012985,
%T 9809425,31952665,104080805,320465225,986713745,3038231465,9355145285,
%U 28937578127,89510467490,276877411436,856448448026,2788351903326,9078078610226,29555650383626
%N a(n) = 1 + a(floor(n/2))*a(ceiling(n/2)) for n > 1, a(1) = 3.
%C All terms are congruent to 3 mod 7.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%p a:= proc(n) option remember; `if`(n=1, 3,
%p 1+(t->a(t)*a(n-t))(iquo(n, 2)))
%p end:
%p seq(a(n), n=1..30); # _Alois P. Heinz_, Jul 04 2019
%Y Cf. A005468, A005469.
%K nonn,easy
%O 1,1
%A _Colin Mallows_