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A141609
a(n) = (a(n-1)*a(n-2) + a(n-1)^2)/a(n-3), with a(1) = a(2) = a(3) = 1.
1
1, 1, 1, 2, 6, 48, 1296, 290304, 1763596800, 2400297571123200, 19846204885558066176000000, 223334408639880528216369404299444224000000, 20780031060559302184531906881808103844643569442380668928000000000000
OFFSET
1,4
LINKS
FORMULA
a(n+1) / a(n) = A006277(n-1). - Michael Somos, Dec 29 2012
MATHEMATICA
a[n_]:= a[n]= If[n<4, 1, (a[n-1]*a[n-2] +a[n-1]^2)/a[n-3]]; Table[a[n], {n, 15}]
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 *)
PROG
(Magma) [n le 3 select 1 else (Self(n-1)*Self(n-2) +Self(n-1)^2)/Self(n-3): n in [1..15]]; // G. C. Greubel, Sep 21 2024
(SageMath)
def a(n): # a = A141609
if n<3: return 1
else: return (a(n-1)*a(n-2) +a(n-1)^2)/a(n-3)
[a(n) for n in range(1, 16)] # G. C. Greubel, Sep 21 2024
CROSSREFS
Sequence in context: A113296 A275462 A063744 * A096313 A346788 A230053
KEYWORD
nonn
AUTHOR
Roger L. Bagula, Aug 22 2008
EXTENSIONS
Edited by N. J. A. Sloane, Aug 24 2008
STATUS
approved