A203528 a(n) = v(n+1)/v(n), where v=A203527.

5, 70, 1512, 33150, 842688, 34594560, 1705017600, 68981673600, 3038555520000, 212396207063040, 16628926183833600, 985240084758930000, 61949330611480166400, 6155242080686899200000, 445283762978503737288000

Offset

1,1

Comments

See A093883 for a discussion and guide to related sequences.

Links

Table of n, a(n) for n=1..15.

Mathematica

t = Table[If[PrimeQ[k], 0, k], {k, 1, 100}];
nonprime = Rest[Union[t]]              (* A018252 *)
f[j_] := nonprime[[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}]  (* A000178 *)
Table[v[n], {n, 1, z}]                 (* A203527 *)
Table[v[n + 1]/v[n], {n, 1, z - 1}]    (* A203528 *)
Table[v[n]/d[n], {n, 1, 20}]           (* A203529 *)

Crossrefs

Cf. A203527, A203529, A018252, A093883, A203416.

Sequence in context: A077691 A277301 A014231 * A147629 A274256 A280574

Adjacent sequences: A203525 A203526 A203527 * A203529 A203530 A203531

Keyword

nonn,easy

Author

Clark Kimberling, Jan 03 2012

Extensions

Definition corrected by Georg Fischer, Nov 26 2021

Status

approved