A081955 a(n) = 2^r*3^s where r = n(n+1)/2 and s = n(n-1)/2.

1, 2, 24, 1728, 746496, 1934917632, 30091839012864, 2807929681968365568, 1572081206902992767287296, 5280985496827154199640037916672, 106440332834866049138191223105387495424, 12872079797383178927229037635891253693013557248

Offset

0,2

Links

Table of n, a(n) for n=0..11.

Formula

a(n+1) = 2^(n+1)*3^n*a(n), a(1) = 2. - Ryan Propper, Jun 15 2005

A171795(n) = a(-n). a(n+1) * a(n-1) = 6 * a(n)^2. - Michael Somos, Dec 17 2009

Mathematica

Do[Print[2^(n*(n+1)/2)*3^(n*(n-1)/2)], {n, 10}] (* Ryan Propper, Jun 15 2005 *)

Prog

(PARI) {a(n) = 3^(n*(n-1)/2) * 2^(n*(n+1)/2)} /* Michael Somos, Dec 17 2009 */

Crossrefs

Sequence contains the product of a row in A081954.

Cf. A025192, A081954, A081956.

Sequence in context: A000479 A181231 A111427 * A292797 A163086 A280922

Adjacent sequences: A081952 A081953 A081954 * A081956 A081957 A081958

Keyword

nonn

Author

Amarnath Murthy, Apr 02 2003

Extensions

More terms from Ryan Propper, Jun 15 2005

Status

approved