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/*
Copyright (C) 2011 Fredrik Johansson
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "fmpz.h"
#include "fmpz_vec.h"
#include "arith.h"
void
arith_bell_number_vec_recursive(fmpz * b, slong n)
{
slong i, k;
fmpz * t;
if (n < BELL_NUMBER_TAB_SIZE)
{
for (i = 0; i < n; i++)
fmpz_set_ui(b + i, bell_number_tab[i]);
return;
}
n -= 1;
t = _fmpz_vec_init(n);
fmpz_one(t);
fmpz_one(b);
fmpz_one(b + 1);
for (i = 1; i < n; i++)
{
fmpz_set(t + i, t);
for (k = i; k > 0; k--)
fmpz_add(t + k - 1, t + k - 1, t + k);
fmpz_set(b + i + 1, t);
}
_fmpz_vec_clear(t, n);
}