A013582 Number of positions in game "Connect Four" (played on usual 6-row, 7-column board) after n moves, up to reflection.

1, 4, 25, 121, 568, 2144, 8231, 27473, 92244, 279241, 831581, 2284733, 6118941, 15465573, 37720667, 88273017, 197300906, 429114775, 881951878, 1784140720, 3373100313, 6336692489, 11005448210, 19131647821, 30415473928, 48633111249

Offset

0,2

Links

Sean A. Irvine, Table of n, a(n) for n = 0..42 [a(42) corrected by Sidney Cadot]

John Tromp, John's Connect Four Playground, viewed Jan 23 2014.

Eric Weisstein's World of Mathematics, Connect-Four

Crossrefs

Cf. A212693.

Sequence in context: A273023 A013187 A069639 * A260373 A362391 A175733

Adjacent sequences: A013579 A013580 A013581 * A013583 A013584 A013585

Keyword

nonn,fini,full

Author

Russ Cox

Extensions

Name clarified by Charles R Greathouse IV, Dec 01 2013

a(3)-a(13) corrected by Sean A. Irvine, Aug 09 2018. The corrected values were confirmed by Russ Cox and extended through a(15), Aug 13 2018

a(16)-a(17) from Sean A. Irvine, Aug 15 2018

Remaining terms a(18)-a(42) from Sean A. Irvine, Oct 02 2018

a(42) corrected by Sidney Cadot, Dec 04 2022, after comparing results of an independent solver and confirming with Sean A. Irvine that the previously given value was indeed erroneous.

Status

approved