A068507 Highly composite numbers sandwiched between twin primes.

4, 6, 12, 60, 180, 240, 7560, 55440, 110880, 73329656400, 18632716502400, 130429015516800, 48519593772249600, 149602080797769600, 74377068101903920953600, 927967188666725711881005276648000, 241271469053348685089061371928480000

Offset: 1

Author

Lekraj Beedassy, Mar 25 2002

Keywords

• nonn

Comments

Intersection of (A072826 - 1) and (A072828 + 1). - Lekraj Beedassy, Nov 27 2003

The next term, a(18), is A002182(1002), it has 77 digits. - M. F. Hasler, Jun 23 2019

a(22) > 10^17030, if it exists. - Amiram Eldar, Dec 03 2020

Examples

			60 is between 59 and 61.
		

Links

• M. F. Hasler and Amiram Eldar, Table of n, a(n) for n = 1..21 (terms 1..20 from M. F. Hasler)
• Brian Hayes, Does having prime neighbors make you more composite?, Bit-Player Article, Nov 04 2021

Crossrefs

Cf. A002182, A072826, A072828, A117825, A321995.

This is also the intersection of A002182 and A014574.

Formula

a(n) = A002182(A321995(n)). - Amiram Eldar, Dec 03 2020

Extensions

Corrected and extended by Lior Manor, Jun 03 2002

More terms from Bill McEachen, May 24 2006

a(18)-a(20) from M. F. Hasler, Jun 23 2019