login
a(n) = lcm_{k=0..n} (k! + 1).
1

%I #15 Jun 12 2022 17:17:55

%S 2,2,6,42,1050,127050,13086150,65967282150,2659866783570150,

%T 13594579130827036650,4484729304047661947505150,

%U 179016047168539016473835519025150,85748973198421705721932588223712809265150,533960639770963461900374948788827304744234574385150

%N a(n) = lcm_{k=0..n} (k! + 1).

%C I came upon this sequence in an attempt to solve an open Erdős problem: Show that Sum_{k>=0} 1/(k!+1) is rational/irrational/transcendental.

%H Harvey P. Dale, <a href="/A137244/b137244.txt">Table of n, a(n) for n = 0..43</a>

%F a(n) = lcm_{k=0..n} (k! + 1).

%t With[{t=Range[0,20]!+1},Table[LCM@@Take[t,n],{n,Length[t]}]] (* _Harvey P. Dale_, Dec 21 2015 *)

%o (PARI) a(n) = {lc = 1; for (k=0, n, lc = lcm(lc, k!+1);); return (lc);} \\ _Michel Marcus_, Jul 25 2013

%Y Cf. A038507, A000142.

%K easy,nonn

%O 0,1

%A _Karl Levy_, Mar 09 2008

%E More terms from _Harvey P. Dale_, Dec 21 2015