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A105110 Direct matrix (non-recursive) content of -n to n+1 symmetry matrices. 0
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: A145419 A276763 A142354 * A064696 A021488 A296040

Adjacent sequences:  A105107 A105108 A105109 * A105111 A105112 A105113

KEYWORD

nonn,uned,tabf,obsc

AUTHOR

Roger L. Bagula, Apr 07 2005

STATUS

approved

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Last modified April 4 21:43 EDT 2020. Contains 333238 sequences. (Running on oeis4.)