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A282389
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Number of squares in triangle-shaped polyominoes obtained by adding three identical polyominoes to the previous one, starting with one L-tetromino.
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2
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4, 10, 25, 70, 238, 901, 3445, 13390, 52942, 210226, 838450, 3350725, 13393093, 53547790, 214151950, 856558645, 3426077749, 13703917774, 54815043790, 219258602290, 877031899954, 3508124454085, 14032487779525, 56129938535185, 224519713993489, 898078755310654
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OFFSET
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0,1
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COMMENTS
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Each polyomino a(n) has a width of A282390(n+1) squares and a height of A000051(n) squares.
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LINKS
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FORMULA
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a(0) = 4; a(n) = a(n-1) + 3*(A282390(n)*A000051(n-1) - a(n-1)) for n > 0.
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PROG
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(Python)
m = [3, 1]
for i in range(25):
w, h = m[0], len(m)
print(sum(m)) # print(w) for widths of the polyominoes
m2 = [w-x for x in reversed(m) if w>x]
m = [w+x for x in m2] + [w for x in m if x==w] + m2
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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