A220772 Number of tilings of a 6 X n rectangle using integer-sided rectangular tiles of equal area.

1, 4, 21, 54, 343, 1225, 7104, 31777, 169952, 819260, 4234749, 21008157, 107087889, 536982808, 2721665059, 13704483996, 69301052416, 349520578291, 1765820428959, 8911657997748, 45005845549969, 227191526564923, 1147192132487813, 5791672997769659

Offset

0,2

Comments

a(n+1)/a(n) tends to r = 5.048917339522305313522214407..., where r is the largest root of 1-5*x+6*x^2-x^3. - Vaclav Kotesovec, Dec 21 2012

Links

Alois P. Heinz, Table of n, a(n) for n = 0..500

Example

a(1) = 4:
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Crossrefs

Column k=6 of A220777.

Sequence in context: A033569 A201446 A371311 * A242135 A332981 A135559

Adjacent sequences: A220769 A220770 A220771 * A220773 A220774 A220775

Keyword

nonn

Author

Alois P. Heinz, Dec 19 2012

Status

approved