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 A203418 Vandermonde determinant of the first n composite numbers (A002808). 6
 1, 2, 16, 240, 11520, 13271040, 254803968000, 15892123484160000, 5126163351050649600000, 89288743527804466888704000000, 50689719717698351557731837542400000000, 125765178831579421305165126665125232640000000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Each term divides its successor, as in A203419, and each term is divisible by the corresponding superfactorial, A000178(n), as in A203420. LINKS MATHEMATICA t = Table[If[PrimeQ[k], 0, k], {k, 1, 100}]; composite = Rest[Rest[Union[t]]] (* A002808 *) f[j_] := composite[[j]]; z = 20 ; v[n_] := Product[Product[f[k] - f[j], {j, 1, k - 1}], {k, 2, n}] d[n_] := Product[(i - 1)!, {i, 1, n}] Table[v[n], {n, 1, z}]              (* A203418 *) Table[v[n + 1]/v[n], {n, 1, z - 1}] (* A203419 *) Table[v[n]/d[n], {n, 1, 20}]        (* A203420 *) CROSSREFS Cf. A203419, A203420, A000040, A002808. Sequence in context: A206884 A188756 A156495 * A207082 A207176 A217812 Adjacent sequences:  A203415 A203416 A203417 * A203419 A203420 A203421 KEYWORD nonn AUTHOR Clark Kimberling, Jan 02 2012 STATUS approved

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Last modified August 13 22:26 EDT 2020. Contains 336464 sequences. (Running on oeis4.)