1,4

F. Harary, Graphical enumeration problems; in Graph Theory and Theoretical Physics, ed. F. Harary, Academic Press, London, 1967, pp. 1-41.

W. F. Lunnon, Counting hexagonal and triangular polyominoes, pp. 87-100 of R. C. Read, editor, Graph Theory and Computing. Academic Press, NY, 1972.

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S. T. Coffin, The Puzzling World of Polyhedral Dissections, Chap 2, Table 1.

R. K. Guy, O'Beirne's Hexiamond, in The Mathemagician and the Pied Puzzler - A Collection in Tribute to Martin Gardner, Ed. E. R. Berlekamp and T. Rogers, A. K. Peters, 1999, 85-96.

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M. Keller, Counting polyforms

Cf. A006534, A030223, A030224, A001420, A096361.

Adjacent sequences: A000574 A000575 A000576 this_sequence A000578 A000579 A000580

Sequence in context: A073713 A084921 A070765 this_sequence A111758 A000942 A000207

nonn,hard,nice

njas

More terms from David W. Wilson (davidwwilson(AT)comcast.net). a(19) from Achim Flammenkamp (achim(AT)uni-bielefeld.de) Feb 15 1999.

a(20), a(21), a(22), a(23) and a(24) from Brendan Owen (brendan_owen(AT)yahoo.com), Jan 01 2002

a(25) to a(28) from Joseph Myers (jsm(AT)polyomino.org.uk), Sep 24 2002