A141609 a(n)=(a(n - 1)*a(n - 2) + a(n - 1)^2)/a(n - 3).

1, 1, 1, 2, 6, 48, 1296, 290304, 1763596800, 2400297571123200, 19846204885558066176000000, 223334408639880528216369404299444224000000, 20780031060559302184531906881808103844643569442380668928000000000000

Offset

1,4

Comments

A sequence constructed to have the pattern of a Somos-type sequence.

Links

Table of n, a(n) for n=1..13.

Formula

a(n+1) / a(n) = A006277(n-1). - Michael Somos, Dec 29 2012

Mathematica

Clear[a, f, t, n, m] a[0] = 1; a[1] = 1; a[2] = 1; a[n_] := a[n] = (a[n - 1]*a[n - 2] + a[n - 1]^2)/a[n - 3]; Table[a[n], {n, 0, 20}]
RecurrenceTable[{a[1]==a[2]==a[3]==1, a[n]==(a[n-1]a[n-2]+a[n-1]^2)/a[n-3]}, a, {n, 14}] (* Harvey P. Dale, Oct 01 2017 *)

Crossrefs

Cf. A006277, A006720.

Sequence in context: A113296 A275462 A063744 * A096313 A346788 A230053

Adjacent sequences: A141606 A141607 A141608 * A141610 A141611 A141612

Keyword

nonn

Author

Roger L. Bagula, Aug 22 2008

Extensions

Edited by N. J. A. Sloane, Aug 24 2008

Status

approved