A105110 Direct matrix (non-recursive) content of -n to n+1 symmetry matrices.

0, 0, 2, 0, 6, 6, 0, 12, 12, 156, 0, 20, 20, 420, 820, 0, 30, 30, 930, 1830, 29730, 0, 42, 42, 1806, 3570, 79422, 229362, 0, 56, 56, 3192, 6328, 185080, 539448, 10903928, 0, 72, 72, 5256, 10440, 388872, 1140552, 29139336, 111259080, 0, 90, 90, 8190, 16290

Offset

0,3

Comments

Triangle table: {0} {0, 2} {0, 6, 6} {0, 12, 12, 156} {0, 20, 20, 420, 820} {0, 30, 30, 930, 1830, 29730} {0, 42, 42, 1806, 3570, 79422, 229362}

Links

Table of n, a(n) for n=0..49.

Formula

f(w)=Abs[Det[Table[Table[If [n > m, -q, If[ n == m, 0, q + 1]], {n, 0, w}], {m, 0, w}]]] a(n)=f(w) while q>=w

Mathematica

f[w_] := Abs[Det[Table[Table[If [ n > m, -q, If[ n == m, 0, q + 1]], {n, 0, w}], {m, 0, w}]]] (* triangular table*) a = Table[Table[f[w], {w, 0, q}], {q, 0, 20}] (* output array*) b = Flatten[a]

Crossrefs

Sequence in context: A276763 A338465 A142354 * A351884 A342501 A064696

Adjacent sequences: A105107 A105108 A105109 * A105111 A105112 A105113

Keyword

nonn,uned,tabf,obsc

Author

Roger L. Bagula, Apr 07 2005

Status

approved