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Number of cases considered in a particular algorithm for enumerating hexaflexagrams.
(Formerly M0598)
1

%I M0598 #19 Jul 13 2022 02:07:45

%S 2,3,4,12,20,55,127,371,1037,3249,10071,32913,108112,363618,1233938,

%T 4244102,14716095,51480027,181312939

%N Number of cases considered in a particular algorithm for enumerating hexaflexagrams.

%C See O'Reilly reference for precise definition.

%D Thomas J. O'Reilly, Classifying and Counting Hexaflexagrams, J. Rec. Math., 8 (1976), 182-187.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Sean A. Irvine, <a href="https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a007/A007499.java">Java program</a> (github)

%H Thomas J. O'Reilly, <a href="/A007499/a007499.pdf">Classifying and Counting Hexaflexagrams</a>, J. Rec. Math., 8 (1976), 182-187. [Annotated scanned copy]

%Y Cf. A000207.

%K nonn,more

%O 1,1

%A _N. J. A. Sloane_, _Robert G. Wilson v_, circa 1976.

%E Title clarified and a(11)-a(19) from _Sean A. Irvine_, Jul 12 2022