%I
%S 0,1,1,2,1,4,2,7,1,10,4,15,2,21,7,30,1,38,10,49,4,63,15,82,2,99,21,
%T 122,7,150,30,187,1,218,38,257,10,305,49,364,4,417,63,484,15,562,82,
%U 659,2,743,99,844,21,964,122,1107,7,1236,150,1393,30,1573,187,1790,1,1978,218
%N Semitribonacci numbers, from tribonacci by analogy with semifibonacci sequence.
%H T. D. Noe, <a href="/A074364/b074364.txt">Table of n, a(n) for n = 0..10000</a>
%H M. J. Halm, <a href="http://untilheaven.tripod.com/id112.htm">Sequences</a>
%F a(0) = 0, a(1) = 1, a(2n) = a(n), a(2n+1) = a(2n)+a(2n1)+a(2n2)
%e a(4)=1 because a(4/2)=a(2)=1.
%Y Cf. A030067, A000073.
%K nonn
%O 0,4
%A _Michael Joseph Halm_, Feb 13 2003
