A065068 Number of fixed polyominoes with n cells of which no four are equally spaced on a straight line.

1, 2, 6, 17, 45, 114, 264, 545, 1061, 2070, 3990, 7275, 12556, 20824, 33584, 52753, 80560, 119274, 170168, 232700, 306472, 396580, 517300, 688736, 926816, 1241720, 1640968, 2130448, 2710356, 3383596, 4171788, 5120776, 6289760, 7747928, 9582196, 11908872, 14887792, 18732340, 23712492, 30141180, 38341172, 48622328, 61275752, 76578628, 94786504, 116132688, 140870564, 169379536, 202262720, 240326780, 284337040, 334532714, 389976092

Offset

1,2

Comments

a(142) = 36 is the final nonzero term of this sequence. - Jan Kristian Haugland, Apr 28 2020

Links

Table of n, a(n) for n=1..53.

Jan Kristian Haugland, Illustration for n = 142 [Cached copy, with permission]

J. K. Haugland, Largest polyomino with no four cells equally spaced on a straight line, arXiv:2004.12801 [math.GM] (2020).

Wikipedia, Polyomino

Formula

a(n) = 0 for n >= 143. - Jan Kristian Haugland, Apr 28 2020

Crossrefs

Cf. A001168.

Sequence in context: A000996 A309757 A020963 * A109961 A288029 A268655

Adjacent sequences: A065065 A065066 A065067 * A065069 A065070 A065071

Keyword

nonn

Author

Jan Kristian Haugland, Nov 07 2001

Extensions

a(32)-a(53) from Brendan Owen (brendan_owen(AT)yahoo.com), Mar 11, 2002

Status

approved