A195524 Number of lower triangles of a 6X6 -n..n array with all row and column sums zero

6247, 860017, 23663523, 286168923, 2106810049, 11131321791, 46387885537, 161770028369, 491117662815, 1334411256817, 3311007744155, 7616624997827, 16434220066785, 33565300493927, 65367853464305, 122110269851089

Offset

1,1

Comments

Row 6 of A195522

Links

R. H. Hardin, Table of n, a(n) for n = 1..37

Formula

Empirical: a(n) = (7389349/90720)*n^10 + (7389349/18144)*n^9 + (836251/864)*n^8 + (4318165/3024)*n^7 + (6254923/4320)*n^6 + (4563293/4320)*n^5 + (10247161/18144)*n^4 + (249983/1134)*n^3 + (21959/360)*n^2 + (3469/315)*n + 1

Example

Some solutions for n=4
..0............0............0............0............0............0
..2-2.........-1.1.........-1.1.........-4.4..........0.0..........0.0
..3-4.1.......-1.3-2.......-1-3.4........1-2.1........0-1.1.......-2.1.1
.-1.3-4.2.....-2.4.2-4......2-3.2-1......1.3.0-4.....-2.2.3-3.....-2.4.0-2
.-1.3-1-2.1....1-4.4.2-3....3.4-3-3-1...-2-1.1.3-1...-1-1.0.1.1....1-1-2.0.2
.-3.0.4.0-1.0..3-4-4.2.3.0.-3.1-3.4.1.0..4-4-2.1.1.0..3.0-4.2-1.0..3-4.1.2-2.0

Crossrefs

Sequence in context: A071130 A031577 A031757 * A045187 A223465 A035904

Adjacent sequences: A195521 A195522 A195523 * A195525 A195526 A195527

Keyword

nonn

Author

R. H. Hardin Sep 20 2011

Status

approved