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A001573
Another approximation to A000084(n).
(Formerly M1190 N0460)
2
1, 2, 4, 9, 23, 63, 177, 514, 1527, 4625, 14230, 44357, 139779, 444558, 1425151, 4600339, 14939849, 48778197, 160019885, 527200711
OFFSET
1,2
COMMENTS
Appears to have been calculated with very low precision. A093156 is a better version. - Pab Ter (pabrlos(AT)yahoo.com), May 11 2004
REFERENCES
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.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
J. Riordan and C. E. Shannon, The number of two-terminal series-parallel networks (annotated scanned copy)
CROSSREFS
Sequence in context: A337721 A369328 A058585 * A135307 A000083 A092668
KEYWORD
nonn,more
STATUS
approved