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A055463 a(n) = 2*a(n-1)*a(n-2) - 3*a(n-3), with a(0) = 0, a(1) = 1, a(2) = 2. 1
0, 1, 2, 4, 13, 98, 2536, 497017, 2520869930, 2505830419990012, 12633745110864184300787269, 63316045634407119326463714272245870904666, 1599837563945889048330164752080268110156603845860584259478831024272 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
FORMULA
a(3*n+1) == 1 (mod 12), a(3*n+2) == 2 (mod 12), a(3*n+3) == 4 (mod 12). - Robert Israel, Jan 18 2018
MAPLE
A[0]:= 0: A[1]:= 1: A[2]:= 2:
for n from 3 to 17 do A[n]:= 2*A[n-1]*A[n-2]-3*A[n-3] od:
seq(A[i], i=0..17); # Robert Israel, Jan 18 2018
MATHEMATICA
a[n_]:= a[n]= If[n<3, n, 2*a[n-1]*a[n-2] -3*a[n-3]];
Table[a[n], {n, 0, 15}] (* G. C. Greubel, Jan 31 2024 *)
PROG
(Magma)
function a(n) // a = A055463
if n le 2 then return n;
else return 2*a(n-1)*a(n-2) - 3*a(n-3);
end if;
end function;
[a(n): n in [0..15]]; // G. C. Greubel, Jan 31 2024
(SageMath)
def a(n): # a = A055463
if (n<3): return n
else: return 2*a(n-1)*a(n-2) - 3*a(n-3)
[a(n) for n in range(16)] # G. C. Greubel, Jan 31 2024
CROSSREFS
Sequence in context: A306445 A216670 A103845 * A369313 A091957 A327443
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Jul 05 2000
STATUS
approved

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Last modified March 28 12:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)