A203528 - OEIS

%I #11 Nov 26 2021 06:39:05

%S 5,70,1512,33150,842688,34594560,1705017600,68981673600,3038555520000,

%T 212396207063040,16628926183833600,985240084758930000,

%U 61949330611480166400,6155242080686899200000,445283762978503737288000

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

%C See A093883 for a discussion and guide to related sequences.

%t t = Table[If[PrimeQ[k], 0, k], {k, 1, 100}];

%t nonprime = Rest[Union[t]]              (* A018252 *)

%t f[j_] := nonprime[[j]]; z = 20;

%t v[n_] := Product[Product[f[k] + f[j], {j, 1, k - 1}], {k, 2, n}]

%t d[n_] := Product[(i - 1)!, {i, 1, n}]  (* A000178 *)

%t Table[v[n], {n, 1, z}]                 (* A203527 *)

%t Table[v[n + 1]/v[n], {n, 1, z - 1}]    (* A203528 *)

%t Table[v[n]/d[n], {n, 1, 20}]           (* A203529 *)

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

%K nonn,easy

%O 1,1

%A _Clark Kimberling_, Jan 03 2012

%E Definition corrected by _Georg Fischer_, Nov 26 2021