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A203416 v(n+1)/v(n), where v=A203415. 4
3, 10, 56, 120, 432, 12672, 249600, 873180, 4838400, 296110080, 10786406400, 49621572000, 355053404160, 34613526528000, 211189410432000, 1910897049600000, 21311651380219200, 274774815041126400, 62908970812047360000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..19.

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. A203415, A203417, A000040, A018252.

Sequence in context: A081721 A013009 A301920 * A002218 A107871 A111270

Adjacent sequences:  A203413 A203414 A203415 * A203417 A203418 A203419

KEYWORD

nonn

AUTHOR

Clark Kimberling, Jan 01 2012

STATUS

approved

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Last modified August 13 22:57 EDT 2020. Contains 336473 sequences. (Running on oeis4.)