A137244 a(n) = lcm_{k=0..n} (k! + 1).

2, 2, 6, 42, 1050, 127050, 13086150, 65967282150, 2659866783570150, 13594579130827036650, 4484729304047661947505150, 179016047168539016473835519025150, 85748973198421705721932588223712809265150, 533960639770963461900374948788827304744234574385150

Offset: 0

Author

Karl Levy, Mar 09 2008

Keywords

• easy
• nonn

Comments

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.

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..43

Crossrefs

Cf. A038507, A000142.

Programs

Mathematica

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

PARI

a(n) = {lc = 1; for (k=0, n, lc = lcm(lc, k!+1);); return (lc);} \\ Michel Marcus, Jul 25 2013

Formula

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

Extensions

More terms from Harvey P. Dale, Dec 21 2015