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

 

Logo

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 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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

Table of n, a(n) for n=1..12.

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

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