A105110 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

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

(list; graph; refs; listen; history; text; internal format)

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