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Number of triangular polyominoes (or polyiamonds) with perimeter at most n.
0

%I #7 Jan 16 2023 09:02:51

%S 0,0,1,2,3,7,12,28,65,185

%N Number of triangular polyominoes (or polyiamonds) with perimeter at most n.

%C Partial sums of A057729 - Number of triangular polyominoes (or polyiamonds) with perimeter n. a(n+2) >= A130867(n) - Triangular polyominoes (or polyiamonds) with n cells at most.

%Y Cf. A131481 (number of n-cell polyiamonds with perimeter n+2).

%K hard,more,nonn

%O 1,4

%A _Tanya Khovanova_, Aug 10 2007

%E Offset corrected by _John Mason_, Jan 16 2023