A089539 - OEIS

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

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..23.

FORMULA

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

MATHEMATICA

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

CROSSREFS

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

Sequence in context: A334009 A069549 A118069 * A324010 A117416 A174943