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A203769
a(n) = (A203768(n+2) - 1)/2.
2
0, 0, 1, 5, 30, 479, 35369, 36141988, 2591378388181, 187498452473472843625, 971772428248668220494932383712302, 364411657942488572318753161467113186052857526280591219
OFFSET
1,4
MATHEMATICA
a[1] = 0; a[2] = 0; a[3] = 1;
a[n_] := SymmetricPolynomial[2, {a[n - 1], a[n - 2], 1 + a[n - 3]}]
Table[a[n], {n, 1, 16}] (* A203768 *)
(Rest[Rest[%]] - 1)/2 (* A203769 *)
CROSSREFS
Sequence in context: A380607 A052172 A058783 * A264861 A264864 A297472
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jan 07 2012
EXTENSIONS
Definition corrected by Georg Fischer, May 04 2022
STATUS
approved