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A330581
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a(0) = 2; thereafter a(n) = a(n - 1)^n + 1.
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0
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OFFSET
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0,1
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COMMENTS
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Note that this could be extended backwards to a(-1), and any nonzero value x for a(-1) would work, since x^0 + 1 = 2.
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LINKS
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MAPLE
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a:= proc(n) option remember; `if`(n<0, %,
1 + a(n-1)^n)
end:
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MATHEMATICA
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a[0] = 2; a[n_] := a[n] = a[n - 1]^n + 1; Array[a, 6, 0] (* Amiram Eldar, Dec 19 2019 *)
nxt[{n_, a_}]:={n+1, a^(n+1)+1}; NestList[nxt, {0, 2}, 5][[;; , 2]] (* Harvey P. Dale, Dec 10 2023 *)
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PROG
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(Lisp) (defun a (n) (+ (if (zerop n) 1 (expt (a (- n 1)) n)) 1))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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