Number of squares in triangle-shaped polyominoes obtained by adding three identical polyominoes to the previous one, starting with one L-tetromino.

A282389

Number of squares in triangle-shaped polyominoes obtained by adding three identical polyominoes to the previous one, starting with one L-tetromino.

Terms

    a(0) =4a(1) =10a(2) =25a(3) =70a(4) =238a(5) =901a(6) =3445a(7) =13390a(8) =52942a(9) =210226a(10) =838450a(11) =3350725a(12) =13393093a(13) =53547790a(14) =214151950a(15) =856558645a(16) =3426077749a(17) =13703917774a(18) =54815043790a(19) =219258602290a(20) =877031899954

External references