1,1

a(4) has 154 digits and is too large to be included.

Table of n, a(n) for n=1..3.

a(n) = (2*A303737(n))! + A303737(n)! - 1.

f:=factorial: select(isprime, [seq(f(2*k)+f(k)-1, k=1..600)]);

Cf. A242487, A300947, A303737.

Sequence in context: A272166 A291881 A257968 * A055578 A232733 A106025

Adjacent sequences: A303735 A303736 A303737 * A303739 A303740 A303741

nonn

Muniru A Asiru, May 27 2018

approved