Number of fixed 2-dimensional triangular-celled animals with n cells (n-iamonds, polyiamonds) in the 2-dimensional hexagonal lattice.

A001420

Number of fixed 2-dimensional triangular-celled animals with n cells (n-iamonds, polyiamonds) in the 2-dimensional hexagonal lattice.

Terms

    a(0) =2a(1) =3a(2) =6a(3) =14a(4) =36a(5) =94a(6) =250a(7) =675a(8) =1838a(9) =5053a(10) =14016a(11) =39169a(12) =110194a(13) =311751a(14) =886160a(15) =2529260a(16) =7244862a(17) =20818498a(18) =59994514a(19) =173338962a(20) =501994070a(21) =1456891547a(22) =4236446214a(23) =12341035217a(24) =36009329450a(25) =105229462401a(26) =307942754342a(27) =902338712971

External references