%I A001573 M1190 N0460
%S A001573 1,2,4,9,23,63,177,514,1527,4625,14230,44357,139779,444558,1425151,
%T A001573 4600339,14939849,48778197,160019885,527200711
%N A001573 Another approximation to A000084(n).
%C A001573 Appears to have been calculated with very low precision. A093156 is a 
               better version. - Pab Ter (pabrlos(AT)yahoo.com), May 11 2004
%D A001573 J. Riordan and C. E. Shannon, The number of two-terminal series-parallel 
               networks, J. Math. Phys., 21 (1942), 83-93. Reprinted in Claude Elwood 
               Shannon: Collected Papers, edited by N. J. A. Sloane and A. D. Wyner, 
               IEEE Press, NY, 1993, pp. 560-570.
%D A001573 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A001573 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%Y A001573 Cf. A000084, A058585.
%Y A001573 Sequence in context: A032028 A127384 A058585 this_sequence A135307 A000083 
               A092668
%Y A001573 Adjacent sequences: A001570 A001571 A001572 this_sequence A001574 A001575 
               A001576
%K A001573 nonn
%O A001573 1,2
%A A001573 N. J. A. Sloane (njas(AT)research.att.com).