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 A203415 Vandermonde determinant of the first n nonprimes (A018252). 5
 1, 3, 30, 1680, 201600, 87091200, 1103619686400, 275463473725440000, 240529195987579699200000, 1163776461866305616609280000000, 344605941225348705438623229542400000000, 3717059729911125118574880410324812431360000000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Each term divides its successor, as in A203416, and each term is divisible by the corresponding superfactorial, A000178(n), as in A203417. LINKS MATHEMATICA t = Table[If[PrimeQ[k], 0, k], {k, 1, 100}]; nonprime = Rest[Union[t]]; f[j_] := nonprime[[j]]; z = 20; (* A018252 *) 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}] (* A203415 *) Table[v[n + 1]/v[n], {n, 1, z - 1}] (* A203416 *) Table[v[n]/d[n], {n, 1, 20}] (* A203417 *) CROSSREFS Cf. A203416, A203417, A000040, A018252. Sequence in context: A012008 A335710 A341499 * A203520 A238767 A323819 Adjacent sequences: A203412 A203413 A203414 * A203416 A203417 A203418 KEYWORD nonn AUTHOR Clark Kimberling, Jan 01 2012 STATUS approved

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Last modified December 1 21:09 EST 2022. Contains 358484 sequences. (Running on oeis4.)