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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..30.

Ed Pegg, Jr., Illustrations of polyforms

Eric Weisstein's World of Mathematics, Polyiamond

CROSSREFS

Sequence in context: A181065 A282239 A191792 * A082095 A177486 A006982

Adjacent sequences:  A151515 A151516 A151517 * A151519 A151520 A151521

KEYWORD

nonn,hard,more

AUTHOR

Ed Pegg Jr, May 13 2009

EXTENSIONS

a(21)-a(30) from Joseph Myers, Nov 27 2010

STATUS

approved

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Last modified July 11 17:24 EDT 2020. Contains 335626 sequences. (Running on oeis4.)