A089539 a(n) is the least semiprime > n!.

4, 4, 9, 25, 121, 721, 5041, 40321, 362885, 3628801, 39916803, 479001617, 6227020801, 87178291201, 1307674368007, 20922789888002, 355687428096003, 6402373705728023, 121645100408832001, 2432902008176640001, 51090942171709440011, 1124000727777607680029, 25852016738884976640003

Offset: 1

Author

Ray Chandler, Nov 09 2003

Keywords

• nonn

Crossrefs

Cf. A001358, A085747, A089538, A089540, A089541, A089542.

Programs

Mathematica

lsn[n_]:=Module[{sp=n!+1},While[PrimeOmega[sp]!=2,sp++];sp]; Array[lsn,25] (* Harvey P. Dale, Mar 30 2024 *)

Formula

a(n) = n! + A085747(n).

Extensions

Better name, more terms from Jinyuan Wang, Jul 31 2021