A122024 a(n) = (3*a(n - 1)a(n - 5) - a(n - 2)*a(n - 4))/a(n - 6); a(0) = 1, a(1) = 1, a(2) = 1, a(3) = 1, a(4) = 1, a(5) = 1.

1, 1, 1, 1, 1, 1, 2, 5, 13, 34, 76, 286, 1651, 10933, 76130, 418553, 3071419, 37191253, 597219127, 11052077737, 158194282219, 2500524791374, 60075261409487, 2150997470890553, 103505410541423890, 3957922747010968084

Offset: 0

Author

Roger L. Bagula, Sep 12 2006

Keywords

• nonn
• easy

Crossrefs

Cf. Somos-6 sequence A006722.

Programs

Mathematica

a[n_] := a[n] = (3*a[n - 1]a[n - 5] - a[n - 2]*a[n - 4])/a[n - 6]; a[0] = 1; a[1] = 1; a[2] = 1; a[3] = 1; a[4] = 1; a[5] = 1; Table[a[n], {n, 0, 30}]
RecurrenceTable[{a[0]==a[1]==a[2]==a[3]==a[4]==a[5]==1,a[n]==(3a[n-1] a[n-5]- a[n-2]a[n-4])/a[n-6]},a,{n,30}] (* Harvey P. Dale, Nov 07 2013 *)

Extensions

Edited by N. J. A. Sloane, Sep 13 2006

Offset changed to 0 by Georg Fischer, Jun 18 2021