A056625 a(n) is the total area of all self-avoiding polygons of length 2n on the square lattice.

1, 4, 22, 124, 726, 4352, 26614, 165204, 1037672, 6580424, 42062040, 270661328, 1751614248, 11391756176, 74406502814, 487838450116, 3209229661682, 21175301453040, 140097533633112, 929160187609096

Offset

2,2

Links

I. Jensen, Table of n, a(n) for n = 2..43 (from link below)

I. Jensen, More terms

Crossrefs

Cf. A002931, A056631.

Sequence in context: A180034 A260346 A136777 * A116428 A121187 A011789

Adjacent sequences: A056622 A056623 A056624 * A056626 A056627 A056628

Keyword

nonn

Author

N. J. A. Sloane, Aug 30 2000

Extensions

Title clarified by Sean A. Irvine, Apr 25 2022

Status

approved