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A151518
Number of 2-sided strip polyiamonds with n cells.
0
1, 1, 1, 2, 3, 5, 8, 15, 25, 46, 80, 145, 256, 466, 833, 1513, 2720, 4925, 8881, 16063, 28996, 52373, 94563, 170620, 307989, 555214, 1001774, 1804594, 3254229, 5858448
OFFSET
1,4
LINKS
Eric Weisstein's World of Mathematics, Polyiamond
CROSSREFS
Sequence in context: A181065 A282239 A191792 * A362785 A082095 A177486
KEYWORD
nonn,hard,more
AUTHOR
Ed Pegg Jr, May 13 2009
EXTENSIONS
a(21)-a(30) from Joseph Myers, Nov 27 2010
STATUS
approved