

A068507


Highly composite numbers sandwiched between twin primes.


9



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

1,1


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


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?, BitPlayer Article, Nov 04 2021


FORMULA

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


EXAMPLE

60 is between 59 and 61.


CROSSREFS

Cf. A002182, A072826, A072828, A117825, A321995.
This is also the intersection of A002182 and A014574.
Sequence in context: A154666 A050537 A114413 * A133454 A061072 A130435
Adjacent sequences: A068504 A068505 A068506 * A068508 A068509 A068510


KEYWORD

nonn


AUTHOR

Lekraj Beedassy, Mar 25 2002


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


STATUS

approved



