1,3

n!!! = n(n-3)(n-6)(n-9)...

The search for multifactorial primes started by Ray Ballinger is now continued by a team of volunteers on the website of Ken Davis (see link).

Table of n, a(n) for n=1..49.

Ray Ballinger, Status of Search for Multifactorial Primes

Ken Davis, Status of Search for Multifactorial Primes.

Ken Davis, Results for n!3+1.

Index entries for sequences related to factorial numbers

Cf. A007661 (triple factorials), A084438, A037082.

Sequence in context: A140102 A288866 A084437 * A188033 A187485 A039052

Adjacent sequences: A037080 A037081 A037082 * A037084 A037085 A037086

nonn

G. L. Honaker, Jr.

More terms from Steven Harvey

Corrected and extended by Hugo Pfoertner, Jun 25 2003

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008

Edited by N. J. A. Sloane, Jan 14 2008

approved